The last few weeks, my pc had the problem of shutting off during bootup. Once it was started up though, it ran perfectly fine until the next time it got booted.
We recently moved to a new house and now it shuts down so frequently that i couldn't get into windows after 3 hours of trying it. So i decided to try a format.
The format of the disk worked but the instal of windows (XP) shuts of at random points.
When i formated the pc i left it on overnight, formatting and loading the windows install did not make it shutdown even after 8hours of idle time.
it doesn't seem to be a heat problem since it runs for a few minutes and it will run for a few minutes again.