PSU kills bios!?

[Michael]

I've have some weird problems with my computer:

A couple of weeks ago my computer wouldn't start up. (black screen, no
beeps, no keyboard lights, but sound of fans and harddrives). After turning
it off/on a couple of times, it worked. This problem reoccured a couple of
times but suddenly I can't get it to start up at all.

I removed everything so only the motherboard (Asus A7V-E, Socket A, KT133),
PSU (300W), RAM (256 MB sdram), video card + monitor and one hd was left.
The pc-speaker and power switch was still connected. When I turn on the psu
and hit the power-switch the fans starts spinning and the hd starts. No
beeps, no video signal.

I then removed everything one by one, but still no beeps (the pc-speaker has
been tested and does work) or any change in reaction from mobo when
power-on. Even removing the mobo battery and/or the cpu doesn't change a
thing (if hd is connected it still powers-up) I have checked the voltages
from the psu after I turned on the power and the mobo gets 3.3V, +5V, -5V,
+12V, -12V and "Power good"(5V) from psu as described in the mobo manual.

My conclusion: the bios is dead and that's why I doesn't get any error-beeps
or video signal - the "power on self test" (POST) does not occur.

I then bought the cheapest compatible mobo I could find (ECS K7S5A Pro),
which could replace my Asus. Now the computer booted but it rebooted when
Win XP tried to start. I tried to change a couple of things in bios setup
and even tried to reset bios, both by taking out the battery and by using
the bios reset jumper. No change - Win XP still wouldn't start. In the
process of rebooting and trying to get the computer to work, it suddenly
wouldn't boot at all!

Exactly the same problem as before: the bios is dead (I assume that is the
problem)

I don't think the CPU (AMD Athlon 1000MHz) is the problem, because it worked
in the beginning with the new ESC mobo.

But why does my bios die when using two different mobos? Could it be my PSU
that (after some time) kills the bios??

I guess I have to buy a third mobo and a new PSU and then if everything
works, I have to try if I can kill the bios again with my old PSU.

Please write if you have any ideas of how I can solve this!!!

 

[kony]

I've have some weird problems with my computer:

A couple of weeks ago my computer wouldn't start up. (black screen, no
beeps, no keyboard lights, but sound of fans and harddrives). After turning
it off/on a couple of times, it worked. This problem reoccured a couple of
times but suddenly I can't get it to start up at all.

I removed everything so only the motherboard (Asus A7V-E, Socket A, KT133),
PSU (300W), RAM (256 MB sdram), video card + monitor and one hd was left.
The pc-speaker and power switch was still connected. When I turn on the psu
and hit the power-switch the fans starts spinning and the hd starts. No
beeps, no video signal.

I then removed everything one by one, but still no beeps (the pc-speaker has
been tested and does work) or any change in reaction from mobo when
power-on. Even removing the mobo battery and/or the cpu doesn't change a
thing (if hd is connected it still powers-up) I have checked the voltages
from the psu after I turned on the power and the mobo gets 3.3V, +5V, -5V,
+12V, -12V and "Power good"(5V) from psu as described in the mobo manual.

Power supply failure can introduce power instability that while still
giving a reasonable voltage reading.

My conclusion: the bios is dead and that's why I doesn't get any error-beeps
or video signal - the "power on self test" (POST) does not occur.

Very unlikely. Of all the failure modes the BIOS isn't a common one,
and not likely here either. Probably motherboard or power supply,
though any component with a problem could prevent the POST.

I then bought the cheapest compatible mobo I could find (ECS K7S5A Pro),
which could replace my Asus. Now the computer booted but it rebooted when
Win XP tried to start. I tried to change a couple of things in bios setup
and even tried to reset bios, both by taking out the battery and by using
the bios reset jumper. No change - Win XP still wouldn't start. In the
process of rebooting and trying to get the computer to work, it suddenly
wouldn't boot at all!

What exactly do you mean? It won't POST at all?
I suspect the power supply.

Exactly the same problem as before: the bios is dead (I assume that is the
problem)

Again, not likely. You are jumping to a conclusion not supported by
evidence. The easiest way to check the BIOS chip would be to remove
it (if possible) and try reading it in another (device). The odds of
the problem being the BIOS chip are so slight that I don't feel it's
even worth checking or considering at this point.

I don't think the CPU (AMD Athlon 1000MHz) is the problem, because it worked
in the beginning with the new ESC mobo.

But why does my bios die when using two different mobos? Could it be my PSU
that (after some time) kills the bios??

Not likely. It might kill the REST of the motherboard, but most
likely it's just the power supply that died, your first motherboard is
probably fine. Due to variations in motherboard design and power
usage, a failing, borderline power supply might not work at all on one
board then barely work on another... since your power supply had
apparently, recently reached this borderline state which prompted the
replacement motherboard, it's even more likely.

I guess I have to buy a third mobo and a new PSU and then if everything
works, I have to try if I can kill the bios again with my old PSU.

Please write if you have any ideas of how I can solve this!!!

I would try to get my hands on another power supply.. borrow one if
you can. It's quite possible that the first motherboard works fine
still, that you don't need the new one and might see if it can be
returned.

You never mentioned the make/model of power supply.


Dave

 

[Michael]

Power supply failure can introduce power instability that while still

giving a reasonable voltage reading.


Very unlikely. Of all the failure modes the BIOS isn't a common one,
and not likely here either. Probably motherboard or power supply,
though any component with a problem could prevent the POST.

But even if it is not the bios that is the problem, it still seems like
something permanent is broken on the motherboards. The new mobo worked in
the beginning and now is has the exact same problem as the old one.

I would try to get my hands on another power supply.. borrow one if
you can. It's quite possible that the first motherboard works fine
still, that you don't need the new one and might see if it can be
returned.

I will try to borrow a psu tonight and try both mobos. The new motherboard
can be returned within 14 days so that is not a problem.

You never mentioned the make/model of power supply.

It's a Silent Systems Q-Tech 300W ATX, almost 2 years old.

 

[Guest]

A couple of weeks ago my computer wouldn't start up. (black screen,
no beeps, no keyboard lights, but sound of fans and harddrives).
After turning it off/on a couple of times, it worked. This problem
reoccured a couple of times but suddenly I can't get it to start up
at all.

I have checked the voltages from the psu after I turned on the
power and the mobo gets 3.3V, +5V, -5V, +12V

My conclusion: the bios is dead

I then bought the cheapest compatible mobo I could find (ECS K7S5A
Pro), which could replace my Asus. Now the computer booted but it
rebooted when Win XP tried to start.
In the process of rebooting and trying to get the computer to work,
it suddenly wouldn't boot at all!

Exactly the same problem as before: the bios is dead (I assume that
is the problem)

I don't think the CPU (AMD Athlon 1000MHz) is the problem, because
it worked in the beginning with the new ESC mobo.

I can understand 1 BIOS failing but 2? Unlikely. And with many
motherboards the keyboard lights will blink even without a valid BIOS
or even without a CPU installed. You need to look at what changed and
what didn't change with the two motherboards: CPU, memory, keyboard,
power supply, and you. The first three things didn't burn up with the
Asus so I doubt they burned up with the ECS. It's possible that you
damaged both motherboards with static in the process of trying to get
them to work, but I somehow doubt that, too. And if you have a
halfway decent 300W power supply (large OEM, like Delta, Astec,
Newton, or quality brand, like Antec, Fortron/Sparkle and not absolute
garbage, like Deer, Q-Tec, Achieve, or A+GPB) it should be good
enough, unless it's developed a fault, such as a burnt resistor or
worn electrolytic capacitor.

Just how did you measure the voltages? They have to be checked with
an accurate meter (about any digtal meter) and under realistic load
(working motherboard will do).

 

[Michael]

Just how did you measure the voltages? They have to be checked with

an accurate meter (about any digtal meter) and under realistic load
(working motherboard will do).

I used a digital multimeter to detect the voltages at the 16 (i power pins
on the back of the motherboard when the mobo was turned on (only cpu
connected). But I guess the psu still could be unstable even if the voltages
seems to be ok, as someone else has mentioned.

One of my friends came up with an idea, that it could be an evil virus that
has infected both my bios's. Is that possible?? I mean a virus that makes my
computer unable to boot? It would explain that the computer works for some
time before it suddenly stops working (it worked fine for 1½ year with the
asus board, and I was able to boot with the new motherboard for about an
hour)

 

[Arge]

Hi Michael

I had the same problem (actually twice), and it was the video card. I am
using a PNY TI-4200. They replaced it once and just sent the replacement
back yesterday.

Bob

 

[kony]

I used a digital multimeter to detect the voltages at the 16 (i power pins
on the back of the motherboard when the mobo was turned on (only cpu
connected). But I guess the psu still could be unstable even if the voltages
seems to be ok, as someone else has mentioned.

One of my friends came up with an idea, that it could be an evil virus that
has infected both my bios's. Is that possible?? I mean a virus that makes my
computer unable to boot? It would explain that the computer works for some
time before it suddenly stops working (it worked fine for 1½ year with the
asus board, and I was able to boot with the new motherboard for about an
hour)

Evil viri?

Odds are it isn't the BIOS, by any method. Now of course you could be
the first person to ever have this happen, or a wicked wife that
slides around on the carpet and zaps your stuff, but I would focus on
the most likely problems first, uhh, unless you CATCH the wife doing
it ;-)

 

[kony]

But even if it is not the bios that is the problem, it still seems like
something permanent is broken on the motherboards. The new mobo worked in
the beginning and now is has the exact same problem as the old one.

We don't know yet that the motherboards have any problem whatsoever,
at least not from the testing you've told us about. Both boards could
be working 100% but the power supply is bad. That is most likely
since the 2nd board is brand-new but not DOA. However, certainly the
worst-case scenario would be that the power supply is killing boards,
but again I don't think it's the BIOS that's being killed.

Consider that perhaps the new board used different voltage rails for
some functions, or simply that it's got fresh capacitors and a
slightly better operation due to that... If the old board had
progressed from working to not working, solely because the power
supply was degrading gradually, then this new board BARELY worked when
you first tried it, but as the power supply further degrades even the
new board won't work... you could easily have two good motherboards
there, only a bad power supply.

I will try to borrow a psu tonight and try both mobos. The new motherboard
can be returned within 14 days so that is not a problem.

While you have the old power supply removed, after it's sat for an
hour, open it up, inspect it, particularly the capacitors around the
output wiring harness and the diodes, resistors.

Also if it has a sleeve-bearing fan, now might be a good time to oil
it (if you hadn't done so already, and if the power supply isn't the
problem.).

It's a Silent Systems Q-Tech 300W ATX, almost 2 years old.

It's a mid-to-low end power supply, so if it really ran silent, that
is that it had low-airflow, it's probably dead because of that.
There's no free lunch when it comes to silence, 2 years is a
reasonable lifespan for a power supply that ran too hot. For a silent
power supply to be good it has to have oversized heatsinks and be
built to a similar design as higher-wattage power supplies, so it's
essentially running far under capacity.

If possible you might also try underclocking the system, see if that
helps. Along the same line of thought (reducing power usage), keep
the system stripped down to minimal, essential parts, and swap in a
different video card if the current card is high-performance.
Minimal parts would include CPU, 1 memory module, CPU fan, video
card.... nothing else is needed to test post. Then progressively add
back parts, like keyboard, mouse, and one drive (HDD) to run windows
testing IF it works underclocked.

If I were guessing though, I'd guess it's a capacitor in the power
supply.


Dave

 

[Michael]

I had the same problem (actually twice), and it was the video card. I am

using a PNY TI-4200. They replaced it once and just sent the replacement
back yesterday.

I've tried with two video-cards on both the motherboards and it didn't help


But thanks anyway...

 

[Michael]

We don't know yet that the motherboards have any problem whatsoever,

at least not from the testing you've told us about. Both boards could
be working 100% but the power supply is bad. That is most likely
since the 2nd board is brand-new but not DOA. However, certainly the
worst-case scenario would be that the power supply is killing boards,
but again I don't think it's the BIOS that's being killed.

Now, I have tried with a power supply from another computer and still same
(or none) results. The setup was again motherboard with CPU (always with
fan), one RAM block, video card (tried two different), one harddrive.

Consider that perhaps the new board used different voltage rails for
some functions, or simply that it's got fresh capacitors and a
slightly better operation due to that... If the old board had
progressed from working to not working, solely because the power
supply was degrading gradually, then this new board BARELY worked when
you first tried it, but as the power supply further degrades even the
new board won't work... you could easily have two good motherboards
there, only a bad power supply.

Well, it still seems like something is wrong with the motherboards, but
maybe caused by the bad power supply in the first case. Today I'm returning
my new motherboard and will hopefulle get another new one. I will then
borrow a power supply and see if I can everything to run.

It's a mid-to-low end power supply, so if it really ran silent, that
is that it had low-airflow, it's probably dead because of that.
There's no free lunch when it comes to silence, 2 years is a
reasonable lifespan for a power supply that ran too hot. For a silent
power supply to be good it has to have oversized heatsinks and be
built to a similar design as higher-wattage power supplies, so it's
essentially running far under capacity.

Hmm. I thought it was ok, because it was twice as expensive as a normal
cheap one. If it is the power supply, which is causing these problems, then
I guess I have to invest in a new one. Any good suggestions?? (not too
expensive, I would rather live with some noise at my current economical
situation).

 

[Michael]

Evil viri?

I've checked the hard drive for viruses and there wasn't any. I know it was
a long shot, but I have to try everything.

Odds are it isn't the BIOS, by any method. Now of course you could be
the first person to ever have this happen, or a wicked wife that
slides around on the carpet and zaps your stuff, but I would focus on
the most likely problems first, uhh, unless you CATCH the wife doing
it ;-)

No wicked wife, and no carpets at all in the whole appartment!!

 

[kony]

Now, I have tried with a power supply from another computer and still same
(or none) results. The setup was again motherboard with CPU (always with
fan), one RAM block, video card (tried two different), one harddrive.

First I will assume that you had tried either board without the hard
drive connected, and with the other memory module... if either of
those have failed you'll get nowhere till you isolate them.

Further I will assume that this new power supply is of adequate
quality and capacity that you can trust that it's suitable for the
system, that if "everything else" were working, the power supply could
be counted on to deliver.

If you have also confirmed that there are no misplaced motherboard
standoffs, possibly shorting the back of the motherboard, and that you
aren't using a CPU fan that's known to have issues of shorting out
(like a "TMD" fan), then were're eliminating some parts and narrowing
it down some. Unfortunately I've heard that the ECS K7S5A has a
higher-than average defect rate, so I feel less comfortable assuming
the new board is (was) 100% working when it arrived there, but without
sufficient additional parts to swap around.

I would still suspect the original power supply and make any further
attempts with this "new" power supply. If you have any old, low-value
equipment lying around, it would be a better testbed for this
questionable old power supply, except that inevitably the older parts
use less power. If you still haven't opened and inspected the old
power supply I'd encourage you to do so, quite often there's visable
evidence of a failure.

Well, it still seems like something is wrong with the motherboards, but
maybe caused by the bad power supply in the first case. Today I'm returning
my new motherboard and will hopefulle get another new one. I will then
borrow a power supply and see if I can everything to run.

That ECS board is also known to require a power supply with a very
healthy 5V rail, many people ended up replacing otherwise good power
supplies to power that board, with those old, replaced power supplies
still working fine to power other similar systems.

Hmm. I thought it was ok, because it was twice as expensive as a normal
cheap one. If it is the power supply, which is causing these problems, then
I guess I have to invest in a new one. Any good suggestions?? (not too
expensive, I would rather live with some noise at my current economical
situation).

Unfortunately the "quiet PC" marketing gimmick is used to sell
anything from junk-to-quality the same as the regularly-marketed
parts, but usually at a price-premium. I glanced at a picture of a
Q-Tec PSU on the 'net, and it looked like the only thing quiet about
it was a cheap low-RPM sleeve-bearing fan.

The best (IMHO) value 300W power supply would be a Forton/Sparkle, not
the OEM-grade with 175W combined 3V/5V rating but rather these:

http://www.newegg.com/app/viewproduct.asp?description=17-104-995
http://www.newegg.com/app/viewproduct.asp?description=17-104-979

I have insufficient data to predict the overall temp or fan lifespan
of the second linked power supply (the one with a 120mm fan) but I did
use one in a system I rebuilt for someone and "so far" it's still
working fine, about a year later. It's pretty quiet but the first
linked PSU is quieter than average too.

Note that when I posted these links, Newegg was doing some maintenance
so both showed "out of stock" but might actually be in stock, or not.

Also any 400W Fortron/Sparkle is a good value, but they don't usually
have air intakes underneath, so in that wattage range you might
consider an Antec instead, or moving towards the lower end (not junk
but less expensive too) an Enlight/ Chieftec/ Highpower/ Thermaltake/
Sirtec (all the same power supply with minor variations like a 2nd fan
underneath). I'd go for the Sparkle or Antec over these latter names
though, because the latter have lower quality mixed bearings (one ball
& one sleeve) per fan. HOWEVER, with any of those latter names, get
a 340W or larger (most common next size up is 360W), since their 300W
isn't as well made.



Dave

 

[Phrederik]

I've checked the hard drive for viruses and there wasn't any. I know it was
a long shot, but I have to try everything.


No wicked wife, and no carpets at all in the whole appartment!!

What I'd suggest is when you get your new mainboard, do the following...

- Build the system on your desk - do not put it in the case - CPU/Sink, RAM,
Video, keyboard and floppy only
- Use a different power supply
- Do NOT connect your hard drive
- At the very first boot, go into the CMOS settings and turn on the BIOS
protection (turn off BIOS flashing) or if the mainboard uses a jumper for
this, disable the jumper.
- Boot from a floppy disk with some kind of system test/burn in or memory
test software.
- Let the test software run for an hour or two.

....at this point you can assume everything is good if it doesn't fail.

Now, do you try your original power supply? How about the hard drive?
Network card? Etc.. Whatever you do, only do them one at a time and test the
PC for an hour or so before moving on. The only problem with this is that
you may end up damaging the new mainboard again.

When you finally do assemble into you chassis, make sure that your standoffs
are all in the right places and there are no extras. Be sure NOT to
connect/disconnect any PS/2 plugs when the power is on.

It sounds like you have a bad PSU, but it really could be anything from bad
RAM, CPU, video card...

 

[Manny]

First my computer stopped working. It would not boot - no
video, no beeps from the speaker. The cpu-fan, the video card
fan and the harddrives started. The first thing I tried was to
change video cards (Asus V9280/TD Ti4200 8X, with an old Nvidea
Riva TNT) - no change. Then I took out all other cards and
unplugged the cd-roms and the harddrives. No change.

I then figured that the motherboard was dead (Asus A7V-E KT 133)
and bought a new one (ECS K7S5A Pro). Now the computer started
and everything worked until winXP was supposed to start. A blue
screen appeared with some un-informative error message and the
computer restarted (could be because of different chipset?). After
about an hour, where I tried different things (removed harddrives,
resetting the bios with jumper, removing and inserting bios-battery)
the computer suddenly would not boot again. It reacted exactly as
with the asus motherboard. I then thought that something was killing
the bios (maybe the power supply).

I sent the ECS motherboard back to the shop, who tested it (they
wrote that it tested ok with AMD XP2200, 256Mb DDR ram and GF3 TI200
and that they have reset the bios). I just got it back and it still
doesn't work. I have borrowed a brand new power supply, ATX 300W
(brand: Power star). My old power supply is a ATX 300W Q Technology
Silent Systems and have worked fine for almost 2 years. The only
thing connected to the motherboard now is the power supply, 256 MB
sdram, video card (tried both), AMD Thunderbird 1000MHz, CPU cooler,
a floppy drive, mouse and keyboard and the system-speaker.

Right now the only thing I can think of trying, is to get a new
block of sdram or ddr ram (the ESC board can use both) and a new
cpu I can try.

If it is the cpu or the ram that is dead, how can it be explained
that the computer worked with the new motherboard for about an hour?
Can I have killed the cpu by taking it out and putting it in several
times and maybe used it without fan connected for a short while?

1. Why didn't you have that shop test and install your CPU, memory,
and video card?

2. Didn't you originally say that you had a Q-Tech supply, which is
a piece of junk, instead of Q Technology, which is much better? I've
never heard of Power Star, but I suspect that it's real garbage, and
you should buy or borrow a known high quality supply, such as a Fortron
or Antec, because without good power, nothing else will work right. A
marginal power supply can often run a computer for some time before it
shuts down permanently or temporarilym and your Asus and ECS
motherboards use the 5V for the CPU power and need a supply with good
"combined power" capacity of the 3.3V and 5V.

3. You should have booted the new motherboard to Safe Mode and then
gone into the Control Panel/System/Device Manager to remove all the
devices and then let Windows redetect the hardware on the next boot.

4. The CPU can stand several seconds without the fan running,
maybe 10-30, but it'll burn up instantly if the heatsink isn't
attached. This is something you want to be sure is absolutely
correct before you turn on the power, others being shorts to
case (normally around motherboard mounting holes and corners)
and power connectors plugged in wrong.

5. Test the memory in another computer or try memory from a known
good computer (the ECS board can even work with PC100 memory if
you set its BIOS for 100 MHz bus speed)

6. When the computer doesn't boot, have you tried hitting the
reset button? Not CTRL-ALT-DEL but the button on the computer.

7. Frankly, you don't know enough to keep yourself out of
trouble. You need to look at what both computers had in common
and what was different between them and concentrate on the
problems that affected both.

 

[Michael]

1. Why didn't you have that shop test and install your CPU, memory,

and video card?

Well, I've always build my computers myself, but with these weird problems
maybe I should have gone to the shop.

2. Didn't you originally say that you had a Q-Tech supply, which is
a piece of junk, instead of Q Technology, which is much better? I've
never heard of Power Star, but I suspect that it's real garbage, and

Yes, I know. I didn't realise at first that Q-tech and Q technology was two
different things. Still I would expect that a power supply would stop
working completly if it breaks after working perfectly for several years.
Instead of suddenly starting to be unstable, which could be the reason for
my problems (I not convinced that the psu is the problem, though)

3. You should have booted the new motherboard to Safe Mode and then
gone into the Control Panel/System/Device Manager to remove all the
devices and then let Windows redetect the hardware on the next boot.

I tried that, when windows would not bot the first time, but the blue screen
still appeared.

4. The CPU can stand several seconds without the fan running,
maybe 10-30, but it'll burn up instantly if the heatsink isn't
attached. This is something you want to be sure is absolutely
correct before you turn on the power, others being shorts to
case (normally around motherboard mounting holes and corners)
and power connectors plugged in wrong.

I am pretty sure, the heatsink allways was attached.

5. Test the memory in another computer or try memory from a known
good computer (the ECS board can even work with PC100 memory if
you set its BIOS for 100 MHz bus speed)

I will test the memory in another computer tonight

6. When the computer doesn't boot, have you tried hitting the
reset button? Not CTRL-ALT-DEL but the button on the computer.

Yes, I tried both

7. Frankly, you don't know enough to keep yourself out of
trouble. You need to look at what both computers had in common
and what was different between them and concentrate on the
problems that affected both

Well, I'll try to test the memory and cpu in other computers a see if that
gets me closer to solving the problem.

 

[Jakub Ner]

Probably your power supply as you suspect. If it had anything to do with
the video card or the memory, the simplest test is to remove either and
listen for those beeps you were expecting, the POST codes.

Regarding the blue screen, once again your intuition is correct, it's a
difference in chipsets. The best thing to do is to start the Win2K/XP setup
process again. I'm not 100% sure about XP, especially XP home, but for
Win2K you pretend to install a fresh copy of windows and ask the setup
program to reuse your old settings from the previous windows
(registry/Documents and Settings/etc). This will make you reinstall all
your Windows drivers, but leave all your programs and other such settings
intact. You do not attempt to fix your OS, as asked at the start of the
Windows setup program, but simply go into the "install" option and opt out
for a partial install there. If you attempt to fix your OS nothing will be
fixed, as that option is minimal, it's for other problems. If you have your
XP on one of those crappy image disks from some brand name, which totally
wipe out your partition, then you will need a complete fresh reinstall.

Personally I think you *do* know enough to troubleshoot yourself.

Regards,
- Jakub

"Michael" <ms@[nospam]3-pac.dk> wrote in message

First my computer stopped working. It would not boot - no
video, no beeps from the speaker. The cpu-fan, the video card
fan and the harddrives started. The first thing I tried was to
change video cards (Asus V9280/TD Ti4200 8X, with an old Nvidea
Riva TNT) - no change. Then I took out all other cards and
unplugged the cd-roms and the harddrives. No change.

I then figured that the motherboard was dead (Asus A7V-E KT 133)
and bought a new one (ECS K7S5A Pro). Now the computer started
and everything worked until winXP was supposed to start. A blue
screen appeared with some un-informative error message and the
computer restarted (could be because of different chipset?). After
about an hour, where I tried different things (removed harddrives,
resetting the bios with jumper, removing and inserting bios-battery)
the computer suddenly would not boot again. It reacted exactly as
with the asus motherboard. I then thought that something was killing
the bios (maybe the power supply).

I sent the ECS motherboard back to the shop, who tested it (they
wrote that it tested ok with AMD XP2200, 256Mb DDR ram and GF3 TI200
and that they have reset the bios). I just got it back and it still
doesn't work. I have borrowed a brand new power supply, ATX 300W
(brand: Power star). My old power supply is a ATX 300W Q Technology
Silent Systems and have worked fine for almost 2 years. The only
thing connected to the motherboard now is the power supply, 256 MB
sdram, video card (tried both), AMD Thunderbird 1000MHz, CPU cooler,
a floppy drive, mouse and keyboard and the system-speaker.

Right now the only thing I can think of trying, is to get a new
block of sdram or ddr ram (the ESC board can use both) and a new
cpu I can try.

If it is the cpu or the ram that is dead, how can it be explained
that the computer worked with the new motherboard for about an hour?
Can I have killed the cpu by taking it out and putting it in several
times and maybe used it without fan connected for a short while?

1. Why didn't you have that shop test and install your CPU, memory,
and video card?

2. Didn't you originally say that you had a Q-Tech supply, which is
a piece of junk, instead of Q Technology, which is much better? I've
never heard of Power Star, but I suspect that it's real garbage, and
you should buy or borrow a known high quality supply, such as a Fortron
or Antec, because without good power, nothing else will work right. A
marginal power supply can often run a computer for some time before it
shuts down permanently or temporarilym and your Asus and ECS
motherboards use the 5V for the CPU power and need a supply with good
"combined power" capacity of the 3.3V and 5V.

3. You should have booted the new motherboard to Safe Mode and then
gone into the Control Panel/System/Device Manager to remove all the
devices and then let Windows redetect the hardware on the next boot.

4. The CPU can stand several seconds without the fan running,
maybe 10-30, but it'll burn up instantly if the heatsink isn't
attached. This is something you want to be sure is absolutely
correct before you turn on the power, others being shorts to
case (normally around motherboard mounting holes and corners)
and power connectors plugged in wrong.

5. Test the memory in another computer or try memory from a known
good computer (the ECS board can even work with PC100 memory if
you set its BIOS for 100 MHz bus speed)

6. When the computer doesn't boot, have you tried hitting the
reset button? Not CTRL-ALT-DEL but the button on the computer.

7. Frankly, you don't know enough to keep yourself out of
trouble. You need to look at what both computers had in common
and what was different between them and concentrate on the
problems that affected both.