8800 GTS 320

I know this card is quite old (2 generations), but it is having serious problems running games that should run fine on it. Call of Duty: World at War runs fine at max settings on 1680x1050 with no AA or AF for a while and then the framerate will drop and the audio will stutter for a few seconds and then return to normal. The same will occur (albeit less frequently) in Team Fortress 2 and Brothers in Arms: Hell's Highway. At first I thought that it might be a temperature issue, but I logged the temperature during an intensive Far Cry 2 benchmark and the core peaked at 64 C and the ambient peaked at 54 C, which I don't think are too high. I also tried re-installing the drivers, which did nothing. What could be the problem here?

Sorry about that my PC specs are:

Intel Core 2 Duo e4400 @ stock
MSI 650i SLI
2 GB Kingston DDR2 RAM
EVGA 8800 GTS 320MB
Coolermaster 700W PSU

Also, the problems have begun after my PC was down for a while due to power issues. Is it possible that perhaps the power connector is properly connected. I didn't do a very slick job of re-attaching everything to my new PSU. Besides that, I reformatted recently and installed the latest WHQL drivers.

EDIT: I am running Windows XP Professional 32-bit SP3, previously Windows Vista Ultimate 64-bit SP1.

you should always double check to be certain that all connections are copa$etic otherwi$e it could co$t you lot$,if by the latest nvidia drivers you mean the 180.48,i too had problems with them [8800gt] went back to the last 178.24 set problems all gone...