Computer shuts down...

It is more likely to happen when I walk away from it - it will shut down within 5-25 minutes. It USUALLY shuts down when I try to play an online video such as a movie trailer etc. It ALWAYS shuts down (within 5 minutes) when I run spyware/virus scan or disc defragmenter etc. I haven't been able to run these scans for 8 weeks now.

Also, my computer clock is almost always off by 24 hours. I can reset it, but next time I restart my computer it is off again.

What can I do?

Adan


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