Serious Reboot Problem

So my computer rebooted yesterday for no reason... I figured it was the power supply or something dumb like that... So i left it on all night(i'm a folder so it was 100% active all night) and checked it this morning... Still running, i was like "humph, that was weird". So i'm installing some random piece of software about a half an hour ago and decide to click on the updates thing and install them... kablewy... then it dawned on me, it was installing updates yesterday when it rebooted. I figured, heck, it's probably the windows updates, and began installing Visual Studio.NET figuring i was safe if i didn't start installing the updates. Well, i had installed many little things and VS.Net got through the "prerequisites" installation cd and when i threw int he VS.net cd, it lasted about 3 seconds and rebooted again... wtf, so i did the little send error report to microsoft and it said that it did not know exactly what was causing the error, but it did tell me it was a "stop error" being caused by an unknown device driver...

Anyone have any ideas where i should start looking?

I just reinstalled windows 2 days ago and the only new driver i used(the rest i had on my computer) was my wireless card driver(which is disabled currently). Never had this happen before, and the fact that it folds and does everything else but install leads me to believe it is a software thing rather than a heat or stability issue.

quick responses would be greatly appreciated as i need to get VS.Net installed on this thing so I can do my homework.

Thanks, Gary

oh, forgot system specs.

Running XP Pro SP1, no updates obviously lol

3.4c p4 @ stock

1gb geil ddr400 golden dragon @ stock
330w true power
250gb maxtor
250gb wd
120gb maxtor(windows drive)
74gb raptor
liteon dvd burner
sapphire 9800xt w/dna drivers
xp120 w/ 120mm fan full speed

nevermind, i'm sure it's a stability issue... its restarted 3 times since then... hmmm... now for the troubleshooting lol.