Computer Crash Diagnosis?

[Joshua]

My homebuilt, scrupulously-maintained PC, which I built four years ago, just
crashed. Yesterday morning the monitor suddently clicked off, the hard drive
churned, and that was that. Now, when I switch the thing on, the hard drive
light flares as normal but the monitor never wakes up and the computer never
boots. (I know it doesn't boot because a laptop networked with it can't
access shared files.)

Here are the specs: Intel Pentium 4 2.4 GHz, Soyo 645D Dragon Lite
motherboard, 512 MB RAM.

I'm thinking the problem is either (1) the motherboard and/or processor, (2)
the video card, or (3) the power supply, but I can't tell anything by just
looking at these components. Is there any way to pinpoint the problem? (And,
no, I don't have a second PC to use as a test bed.) Thanks to anyone who can
offer advice.

 

[JAD]

my guess the power supply

power supply tester

http://www.mwave.com/mwave/viewspec.hmx?scriteria=BA21965

 

[BigJim]

check to make sure a component has not come loose.
My guess is the power supply.

 

[Jan Alter]

First thing you could do is to test the PS with a multimeter to see that the
correct voltages are running and correct. Also check this website out
http://www.ultimatepcrepair.com/news/18.html
Additionally there are other diagnostic routines you can run on the PS to
check voltages to get an even truer reading of its state and that includes
disconnecting it entirely from the system and using the multimeter and a
spare hard drive as a load.
However, before you do that try simply disconnecting the hard drive and
all peripherals such as the hdd, floppy, CD-ROM drives and then try booting.
If it works it's an appropriate exchange of one of those items.

 

[Joshua]

Thanks very much for the advice and the helpful website. As directed, I was
checking the voltage on one of the unused power connections when I realized
that the PC sounded like it was booting as normal. I got up from under the
desk, looked at the monitor, and sure enough everything was normal.
Whatever. Of course, that only means the problem could resurface at any
moment...

 

[DaveW]

The probability is that either the PSU or the motherboard failed. The
easiest way to diagnose which is to replace the PSU with a known working one
of adequate power output and see if that fixes it. If not, it's the
motherboard. CPU's almost never fail, and the video card failing would not
necessarily give the exact symptoms you are having.

 

[David Maynard]

Thanks very much for the advice and the helpful website. As directed, I was
checking the voltage on one of the unused power connections when I realized
that the PC sounded like it was booting as normal. I got up from under the
desk, looked at the monitor, and sure enough everything was normal.
Whatever. Of course, that only means the problem could resurface at any
moment...

Don't ya just love those?

Sounds like a loose connection somewhere.