My computer keeps restarting while I try to play 3d games. I can play for about 5 minutes, then the screen goes black and the pc speaker makes a very wierd noise all that time...then I have to press the restart button... AMD Thunderbird 1.4 512 SDRAM PC133 GeForce2 MX400 SoundBlaster Live 5.1 2x NIC Windows XP
Sounds like that's probably the issue here. Check to make sure the heatsink is firmly attached and that the thermal pad or thermal goop is still there (does not to be very much---a thin coat is fine). 2nd, what motherboard are you using? and what power supply? I know ECS boards can have fits if not paired with a large enough power supply.