Why is my desktop shutting down (power off) on its own after an hour of operation?
 

This is what I've done:
1) reformatted hard disk and reinstalled OS
2) Scanned for virus
3) Cleaned the processor heat sink/fan. Reapplied new heat dissipation paste under the heat sink.

BTW, its a P4 processor, running on XP. Hope to get more leads as I'm running out of ideas. Cheers. Thx.

Maybe it is a temperature problem, causing the system to shut down automatically to cool down.

Hi,

Some thoughts, though ... xp/windows is not my forté/fav ...

You re-installed everything, so...exclude a virus (well, there is a debate werther windows itself is a virus :) but that aside). By the way, a modern virus will keep your system going, as shutting down is "leaving a trace" of its presence and it would disrupt it's own job.

The question is : who/what shuts the pc down? If it's the os, then you'll not get any restore messages at reboot, if it is the hardware (heat/electrical/...) the os would not have the time to cleanly unmount/shutdown and that would manifest itself in some parts of the system. In w98 (yes, it's that long ago I used windows) there was the disk check (blue screen) ...

A clue?

Luck!

Thor

Are you using the PC when it poweroff? the OS makes a shutdown or it looks like if you unplug the power? try to be a bit more specifyc pls

Its not software problem may be its due to hardware problem check the processor sit correctly or else it may due to motherboard problem

i think that you did n't paste well sometimes it happened. so i hope that if u re paste may be that will be help you out.