Sara said:
Hello..I have a computer which is about 2 years old..It`s not a
specific brand as it was just built from someone buying a
case..motherboard..harddrive etc and piecing it together..It ran
really good for 2 years but then a couple of weeks ago when you went
to turn it on it you`d hear the fan start up for like a second and
then the whole thing was just dead and it wouldn`t start at all....Now
it does nothing..I have a number of old computers around and tried
various power supplies, on-off switches, cords, etc and those aren`t
the problem...Can anyone think of something else basic I should try
first or is the board dead?...Also I have a LOT of personal stuff on
the hard drive I`d like to salvage..If I replace the motherboard (If
that's the problem) will it still somehow start up with the hard drive
as is?..Thanks for any input!
Is the CPU heatsink firmly in place ? If the heatsink was loose
and the processor gets hot enough, the computer can switch off.
Along similar lines, the BIOS on some computers, checks to see if
the CPU fan is spinning. The CPU fan cable typically might have
three wires on it. +12V and GND power the fan. The RPM signal
pulses twice per fan revolution, and the hardware monitor
chip on the motherboard counts the pulses. If the BIOS thinks the
fan has stopped, the BIOS may decide to shut the computer down.
(Obviously, that only happens if the CPU can execute some code, to
do the switch-off. If the CPU is absent, or the BIOS chip has been
pulled, then it shouldn't be able to do that.)
Since you've tried another power supply (and I assume the power
supply is adequate to power the system), then that eliminates
an internal fault in the power supply, as the source of the shutdown.
In terms of the hard drive, if you don't have any backups of the
contents of the drive, then don't use that drive until you
have restored the rest of the hardware to a working state.
You could, for example, purchase a new hard drive, for anywhere
from $50 and up. If you manage to cobble together a computer
from bits and pieces, you could reinstall Windows on the brand
new hard drive. If, on the other hand, the cobbled together
computer, damages the new hard drive somehow, then none of your
old data is lost.
If the computer you eventually get working, seems to be working OK,
then you can connect the old drive to the computer. Then copy the
data from the old drive to the new drive. Now you have two copies.
You can put the old drive away as your "backup". At $50 a pop for
small capacity hard drives, that is a lot better than losing all of
the valuable data you've got.
For more ideas, it helps to give an inventory of the hardware in
the computer. Since the computer is no longer working, you'll have
to do this visually. For example, the motherboard may have a
model number printed in white letters on the motherboard surface.
(There is at least one motherboard company, that puts absolutely
no identifying marks at all on their boards, and if you had one
of those, you'd have a hard time describing what you've got there.)
You can assemble a minimum of components and test. For example, in
the last two systems I've built, I test them one piece at a time,
checking for the correct response as each piece is added. The
entire computer was booted and working, while all the parts were
laying on my table. You could try something similar if you have a
clear area to work.
The simplest test consists of motherboard, power switch (to connect
to PANEL header), and ATX power supply. With the appropriate power
cables connected from the power supply to the motherboard, and the
power switch connected to the motherboard, you should be able to
make the power supply go on and off. For this test, you don't need
the processor installed, or the RAM, or anything else. If the
motherboard won't turn the supply on, and you've tried a couple of
known-good supplies, you might draw a conclusion from that.
If you don't trust the power-on switch, you can unplug it, and use
the reset switch and cable as a substitute. Another trick, is to
locate the power-on pins on the PANEL header. Using a slot head
screwdriver, *carefully* short the two pins together on the
PANEL header, where the power-on switch would normally go. I use
this when I'm too lazy to connect a real switch. This is handy,
when the motherboard is sitting outside the computer, on my work
table. It is difficult to do safely, if the motherboard is still
inside the computer case (so don't try it). If the screwdriver tip
makes it switch on and off, but the power-on switch doesn't, then
you have a bad switch.
HTH,
Paul
