Sure would like to have an easy one for you ... but no, not today. ;-)
Anyway, have a client machine that's being a real pill... it's a pretty decent machine, P4-3gig system, a gig of RAM running WinXP Pro... and it's got a penchant for spontaneous restarts, just BAM! Restart.

So, initially I had the client just change the check box so the machine won't restart if errors occur. No help ... sure was hoping for a blue screen to point me in a direction but no.
Once we got to that point and the restarts were occurring more and more often, several or more times a day, it was time to bring the offending machine in and beat it with a hammer. Okay, maybe not.
So I run it through the course ... run all the tests ... no spyware, malware or anything of that sort. Update Windows... was already running Service Pack 3. Hard drive tests, memory tests and nothing... all seems fine. Ran some stress tests, SIW says the power supply is running a correct levels, nothing odd at all! Blew out the dust and moved the RAM to the empty pair of slots just in case that had anything to do with the price of tea in China. Checked the motherboard for bad capacitors, nope...

Still, no restarts while here in my care ... until I'm on the horn with the client discussing the machine... and BAM! there it goes... no blue screen, just blinks out and restarts. Real special... so now it's obviously some sort of bad karma, okay, maybe not.

Anyway... so I continue on and go further. Track down all motherboard drivers, including the on-board video, BIOS .... the whole ball of wax. Get those all updated ... run more tests again. Can't buy a failure ... not of a test or the machine.

So back to the client it goes ... to just wait and see what's up. Hate that. Also to wait for some more RAM that's on order. He had 512 x 2 ... so got 1gig x 2 for the other 2 slots to bring him up to snuff on memory. Machine is running fine ... went out to install the RAM and all is still fine after 3 days or so. Checked a few things, RAM is playing nice and so no worries... fixed his resolution and off I go.

Another week goes by and saw him yesterday ... damn thing pulled the restart thing the evening prior. So ... pulled the old RAM just in case that's the issue or it's just not playing nice with the new RAM. So he's running with the 2gig of new RAM and we'll see what happens....

So I'm looking for an idea or three from the good people here ... you don't even have to be good! And at this point beating it with a hammer might be in order! ;-)

The only 'odd' thing I have found so far is that the power supply wasn't connected quite right. MB has a 24 pin plug, PS is a 20 +4 ... the +4 wasn't plugged into the MB, just the 20. So whoever built it wasn't the sharpest tool, yes... it's a built machine as opposed to a Dell or otherwise.

So give it a go boys and girls ... give me clues ask me questions and thanks in advance for sure!
~ Paul