I've just moved in to a new apartment. I put my PC in the trunk of my car, and when I hooked everything up in my new place, the computer would shutdown on boot (usually after entering password on Windows 7 login).
Anyhow, I've inspected almost every bit of the PC, and nothing helped. Finally, I noticed that the CPU fan was not fastened to its place, so I tried to fasten it, with partial success. Afterwards, my PC "life time" seemed to last longer, but it would still shut down after a few minutes. Then I tried again to fasten the CPU fan bolts and succeeded - it's now securely fastened to its place, and the PC seems to work just fine, EXCEPT when I try to run StarCraft II, then it shuts down after a few minutes. If I'm not running a game, it (looks as though) doesn't have any problems.
In any case - do you know if the problem was really with the CPU? I guess the CPU heats up more when I try to run a game (usually it's at about ~5% use), but what can I do to fix it?