win2k3 random reboot

[Bob The Great]

first off heres my system

EPOX 8RDA+
AthlonXP 2500+ Barton (runs 123-130f)
Radeon9800 (modded to zalman heatsink)
1GB pc3200 Corsair dual channel (2x512mb)
160GB 7200rpm Seagate Cuda
16x DVD
52x32x52x msi burner
Antec Sonata w antec 380watt PSU

so heres the issue, in XP pro I was having this thing where it would just suddenly reboot everyonce in a while. Seemingly randomly, I might just be surfing the web and listing to music or I might be playing a game. Again cpu temp about 120f. I couldn't figure out what it was and it seemingly suddenly began, and Norton NIS 2k3 didn't find a virus, and no spyware. So I decide to format and since Microsoft sent me Windows 2k3 server for some strange reason I figured I'd try it. I'm tottaly in love with it, but 2 days ago (about 5th day of usuing it) I woke up to find it off, so I turn it back on and go to work. Well I come home to it turned off, so I turn it on and go to school. Again its off when I come home, so I turn it on and start surfing the web. Well after about 3 or 4 hours of mucking about with stoof all my apps close and it says windows is shutting down and the pc turns off! So over night last night I turned it on and left it at the logon screen, and its turned off again in the morning. I have no idea what it is, everything seems to be running perfectly other then this, I just ran memtest through and it came back with no errors after about 4 hours of use. I'm lost, any ideas?

edit: I've installed Norton Antivirus on it as well and again it found nothing

[vass0922]

Have you tried event viewer?

start --> run --> eventvwr

Its a good place to start
It doesn't sound like its resetting if it says its shutting down. Sounds like SOMETHING is telling it to shutdown.

maybe disregard all the various apps, try checking to see what is running.
I think 2k3 should come with msconfig if you want to check that as well.

First things though, is to check event viewer.

[Bob The Great]

I'll check that if the problem persists. I'm actually reformatting that pc now, I was trying to restore an older registry but windows got all freaky and was like screaming at me then like pulled out a knife and tried to kill me so I was like all trying to beat it off me and it said that I had violated the ELUA by messing with it. I was all like "ACK", and started reformatting. So thats a good idea though, I have a bad feeling it may start again because I had no funky programs installed, just my normal list which is pretty basic stuff.

Thanks for the reply