I have an nVidia GTS250 that, in the last couple of months, has decided that it has a problem with newer games. Older games are fine, but anything made in the last couple of years will eventually make the system crash and apparently bluescreen (although I never actually see it). Googling the bluescreen code suggests it's an overheating issue; running a heat monitor reveals my CPU runs at a crisp 60ºC when idle but my GPU sits at 85ºC when idle. Turning on logging and opening up a recent game reveals the GPU temperature climbs to 115ºC while the CPU gets up to around 90ºC by the time it crashes.
I suspect I have two, intertwined issues - the GPU is just way too hot, and I've got airflow problems. (Sticking a housefan in there and taking off both sides of the case stops crashes, although the card still sits at 67ºC and goes up to around 100ºC.) Uninstalling and reinstalling drivers doesn't resolve the issue. Dusting with a can of compressed air didn't do the trick either (the temperatures I'm posting are post-dusting). The heatsink is right near an empty slot on the back of the computer. I'm at a loss as to what's causing the card's heat problems and whether it's fixable.
Some advice for resolving the airflow problems would be helpful as well. My case has four vents that could take fans, one in the front, two in the side (one positioned directly next to the CPU with a funnel attached, one underneath) and one in the back, but only the one in the back appears to have anywhere to screw a fan on.