Shoutbox

well all i no is that my pc is left onj all the time it never gets over heated or anything

oh and are u wired  by network cableto get internet???

Usually viruses display some kind of wierd activity or a message or somthing, But its a possibility

Reccomend him to:
Do a virus scan
Clean the insides of his pc (Remove dust, etc)
Check all power cables.

And if its still not working you probly have a problem in one of your hardware components. Ive seen PSU's suddenly just fail and do that to a pc.

Once I stupidly messed with the bios resulting in my PC shutting down at 2 am every day. Make sure you haven't done anything with it (the bios).