Help...PC randomly reboots

[PurePeon]

I am running windows XP and I have automatically reboot on blue screens disabled...but I am getting random reboots and for the life of me I can't figure it out. Any clues on what I should be looking for? I have a 300W PS running a Celeron 1.2, 2 Hard Drives, DVD burner, video, sound and NIC. Nothing fancy. At first I thought it was the PS. I used to have a 230W PS but I swapped it for the 300W PS.

Help Please.

 

[chocoruacal]

memtest86. Its the easiest place to start. And check Event Viewer for error messages.

EDIT: based on the hardware, that system isn't new, correct? So did this problem pop up out of no where? Have you made any software/driver/hardware changes recently?

 

[PurePeon]

I've recently added a 5.1 Sound Blaster Live. That's about it.