Intel Core 2 Duo E7200 2.53g
2gb G.Skill DDR2 6400
Nvidia Geforce 8800GT 512
Seagate 250gb 16mb buffer 7200
600 watt Coolmax triple 12V Rail PSU.
MSI Mainboard non SLI.
It runs really cool, never passing around 95F, even during games like COD4. But after about two hours of using the machine, it freezes up. No BSOD, just a straight up freeze. Even if games aren't being played it will do the same thing over and over. I've tested the memory (memtest +86) overnight, ran 33 passes, nothing. Tested the PSU with my PS/SPS tester, everything lit up fine. Visual inspection returned nothing. I ran a windows repair (It's Windows XP Pro) and that didn't fix it.
I'm starting to think that it might be DirectX 10. Is that a common occurence? This things literally got nothing on it besides XP Pro, and all four COD games. That's all that's on here.
Any help is appreciated, I'm a PC Tech and I'm even stumped. Running a hard drive test right now though.