RE: Computer Shuts Down By Itself?!
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.