Hello, i am having a problem with my PC. My Setup Pentium D CPU 3.00GHz 2gb RAM NVIDIA Geforce 8600 GTS Gigabyte GA-N650SLI-DS4 Coolmaster Centurian CAC-T05 This problem happens in both Vista and XP. The computer can run fine for hours if i'm just on the internet. However, when I start playing games after about 30 minutes it crashes and reboots. This happens in Vista and XP. Every, single, time. I've tried different software settings, reinstalling drivers etc, yet this does nothing. This makes me think it is a hardware problem. Overheating? I'm not sure. Can anyone tell me what this could be and how I would fix it? Thanks.