Computer Randomly Restarts

[Grinson]

Hi,

A couple of months ago I built my pc. For a while it ran perfect, but a couple of weeks ago it started to shutoff and restart at random moments. I did virus scans and all that jazz and ended up reformatting. Now that I have reformatted it is working better, but not like it was when i first had it.

In the past week it has shutoff twice, both times it was while using Sony Vegas. I have run memtest86, also did a cpu and gpu stress test and still don't know whats causing my problem.

My rig is:

AMD Phenom 965
OCZ DDR1600 (AMD Black Edition - if that helps)
OCZ Mod-x-Stream Pro 600w
Biostar TA790GX-A3
Seagate 500gb
ATI 4890

 

[Grinson]

Are there any further tests I can do to figure out whats wrong?

 

[sk1939]

Have you tried switching out your PSU with a different one, switing out your RAM, and blowing out all the dust?

 

[Grinson]

The computer is clean. Its weird but when i stress tested it the temp's got relatively high but it would shut off. Heck I even play Assassins Creed 2 or Bad Company 2 for hours and nothing happens, but when I open Vegas .. after maybe 5 min it shuts off.

I ran the memtest86 off of the ultimate boot disk and didn't give me any errors, but I'll see if I can get my hands on any other ram, as well as the PSU.