Hi there. my machine is a athlon 64 3000+, with 512meg of DDr ram and running windows xp x64. my problem is that everytime that I play a 3d Game my machine crashes out to a black screen and I have to turn my pc off at the powersuply switch at the back. I have tried using different drivers for my geforce 6800 le and even tried using windows xp 32 bit but still the same. there dosnt seem to be any pattern to this either some times It happens as soon as I fire in unreal 2k4 sometimes as soon as san andreas starts other times I can play for about a hour or so !!!. I tried swopping my ram just in case and no luck so I tried the card in my p4 machine and its fine - can any body tell me what the hell is happening ?