Rusty has a home built Windows 7 Desktop and he is getting a blue screen of death. Leo says that blue screens of death were common in the early days were because of system memory/driver issues. Programming has gotten better though, so most of the BSODs we get now are hardware related or corrupted driver problems. Leo says to make sure his fans are spinning. While he has his computer open, he should clean out the dust. Then he can try rebooting in safe mode. If that works, and it runs OK, then he'll know that the video driver is failing and he'll need to reinstall it. Rusty can also check his hard drive for bad sectors. SpinRite will do that.
It could also be a failing power supply or an unseated stick of RAM. The thermal paste could have dried out, causing the processor to over heat. It can be a lot of different things.