Quote Originally Posted by k5r2anchoe View Post
Well, something like that kept happening to my old computer like 3 years ago, but it turned out to be dust in the vents and it overheated because the vents were clogged with dust. Try clearing the vents and see what happens.
I agree with this. Open up your case and take some compressed air or or a can of compressed air and blow out your computer. Thats probably the main thing wrong with it.

Its also possible that you just have PSU that went bad and need to get a new one. I've seen one go up in smoke before and I was freaking out because I thought it was going to make the fire alarms at my work go off... that would have sucked.