"John M" said:
faulty ram is my first guess. Power supply is 2nd.
John
To check the power supply, get the latest copy of Asus Probe.
Asus Probe will allow you to check power supply voltages.
They should be +3.3V, +5V, and +12V, for the rails that
consume the most power. +12V powers your processor, and that
is the one you want to watch more closely. If it drops below
+11.4V (5% low), it is possible your power supply is bad.
What you can do, is watch Asus Probe while the Prime95 test
below is running, and see if the heavy load that Prime95 puts
on your system, is enough to make the voltage drop more than
5%, as seen in Asus Probe.
Click one of the "tools" links, then look for a copy of "probe"
http://www.asus.com.tw/support/download/item.aspx?ModelName=Tools&Type=All
You can test the memory with memtest86 from
www.memtest.org .
The program will format a blank floppy for you, and as long
as the floppy drive is set in the BIOS boot order, you'll be
able to boot the test program on the floppy. Memtest should
be error free, in order for the memory to pass the test. Memtest
will run your screen at 640x480 resolution, and shows its testing
progress, including a list of any error-filled locations.
You can eject the floppy, and press the "esc" key, to reboot
back into Windows, when you feel you've done enough testing.
A second test is Prime95 (from mersenne.org). Prime95 is a
mathematicians program, for finding prime numbers. It has
a test function in the menu, called the "Torture Test". That
test does a computation with a known answer, and will run the
CPU at 100% utilization. Prime95 is a sensitive test for
correct hardware operation, and if the computer reboots soon
after this test starts, it is likely an indication that
the power supply needs to be replaced or upgraded. If there
are any "rounding errors", that indicates the processor is
not healthy (and then you have to figure out why).
Most power supplies have a label on the side, that shows
the number of amps available at a particular voltage. For
a lightly equipped PC with a P4 processor in it, a good
minimum rating is +12v@15amps. That gives 8.3 amps for
a Prescott 3GHz processor, 1 amp to run the 12V fans, 1 amp
for a ATI 9800pro video card aux power connector, 0.5 amps
for an idling hard drive, and perhaps 1 amp for a CDROM
that has media in the tray. If you have more devices than
that, adjust accordingly. The remaining amps are there,
because you don't really want to run the power supply at
its exact limit all the time.
Another thing to inspect, is the heatsink and fan on the
CPU. Check that the fan is spinning, and that the fan
cable has not fallen off. Occasionally, the fastener that
holds the heatsink on, will let go, and then there is nothing
to hold the heatsink firmly to the processor. (If you
installed the CPU, then you'll know whether you used the
Intel thermal interface material, or used a separate thermal
paste or grease. If using thermal paste, it is a good idea
to disassemble the heatsink/fan once a year, and redo the
paste. If using paste, clean the Intel material off first.
Try not to scrape up the finish on the heatsink. Apply
paste to the top of the processor, using only enough to
fill any air gaps. If a whole bunch squeezes out from the edge
of the processor, you are using too much. You should just
see the paste wet the edge of the processor, when the
heatsink is in place. Too much paste functions as an
insulator, and the reason for using the paste, is the paste
conducts better than an air filled gap would (but
doesn't couduct as well as the metal does).
HTH,
Paul
