My PC, after 30-40 minutes of any game with a 3D element in it, shuts down. It never shuts down while being used normally (email, movies, internet), but consistently when gaming.
I noticed it while playing both Starcraft 2 and Civ5, but then I tested it with Civ4 (7 years old) and it STILL crashes.
I replaced by NVIDIA video card (8800GTS) with my ATI card - and it still crashes.
I thought about overheating, so I checked the temp. Neither the video card nor the CPU(s) go above 75*C.
I thought mad RAM, so did a 10 hour memtest - no errors.
Drivers are all up to date, as is Win7.
Operating System: Windows 7 Home Premium 64-bit (6.1, Build 7600)
Processor: Intel(R) Core(TM)2 Duo CPU E6850 @ 3.00GHz (2 CPUs), ~3.0GHz
Memory: 2048MB RAM
Card name: ATI Radeon HD 5700 Series
Motherboard: Abit IP35 Pro ATX