I built a new system recently and it crashes constantly, sometimes bsod, sometimes frozen screen, sometimes reboot. There doesn't seem to be any particular activity that causes it, though there are some that guarantee a crash, even just leaving the computer idle can cause it to freeze or reboot. This seems to be a hardware problem, can you suggest some diagnostics that'll help me determine what's going on? I'm running windows xp, windows 7 would freeze during installation(installing games also seems to provoke crashes). I did have to restart once or twice while installing xp, but I managed to get through it eventually.