Quote Originally Posted by Vaer View Post
Check the CPU temp first by downloading a utility like coretemp or hwinfo, turn the game on and monitor the temperature. For hwinfo use the sensors table. If it rises really rapidly the heatsink might be loose.
This is a great idea because in addition to helping you determine whether or not there are cooling problems in the first place, it will also pinpoint *where* they are. Is it your CPU that's overheating or your GPU? Some things to check when you hardware is overheating are:
* Fans that stopped running or aren't running fast enough
* The thermal paste between your heatsink and CPU may have degraded, in which case you should buy a higher quality paste and remount the cooler.

All that having been said, you might first want to update your GPU drivers. Sometimes the drivers that ship with it are defective, and updating them is much easier than tinkering with the hardware.