MB, CPU, or PSU problem?

[shortyhome]

I have a p4 3.2 dual core which intermittantly keeps rebooting is there any way to check to see what is causing this? I have removed the GX card, sound card, swapped out the memory, done a virus check, and even done a fresh xp install but it keeps rebooting randomly - somtimes 20 min sometimes after two or three hours. All fans are working fine and i've cleaned the cpu fan from dust. The machine is only 2 years old so i dont think it's the cmos battery. any ideas?

 

[Mondoman]

Try the basic checks: download the free memtest86+ CD image file and burn a bootable CD from it, then boot your system from that. Run memtest86+ overnight to make sure no errors show up.
If that's OK, download Orthos or similar Prime95-based stress testing program and run that for at least a few hours.