Looking for some help

[Snowreap]

check the heatsinks on your video card, underneath the fan(s). if the heatsink is clogged with dirt, it won't matter much whether the fan is running or not -- your video card is going to overheat and shut down.

if your computer reliably crashes in certain games after a certain time, then try opening your computer case and aiming a large, powerful, and probably noisy, fan directly at your video card and see if the behavior changes any. if keeping your video card a little cooler allows your system to run a little longer, then heat is very likely your problem.

I have a couple of Antec spot coolers that I keep on hand in case a particular component develops a heating problem. Last time I used one was on a Radeon HD 4870 card that did just fine cooling the GPU and RAM chips on the 'component' side of the board, but had a problem with the RAM chips on the back side of the board getting too hot.

also, if you have an infrared laser thermometer, that's a useful tool to use to locate hot spots in your PC.

-ken