Originally posted by Warez Monster
Did you get on the net and a box pops up and reads restarting in so many seconds?
From the way that Mouse Potato described the problem, Warez's idea was the closest. There is no way that a faulty PSU could close down all apps, etc. A faulty PSU will turn a computer off instantly.
Warez's idea was something along the lines of the Sasser Worm, among others that automatically turn your computer off.
The best way to combat worms is to go to the Windows Update website and download all of the latest security patches. Plus employing a firewall will also help to keep worms out.