Windows Closing Down?

[livesound66]

Hi All,
For no apparent reason my PC/Windowm XP(Home) has started suddenly closing down,and all I have is a blank screen.
I had been doing "housekeeping" over the weekend and had run SpyBot and RegCure and let them both fix/remove various errors, after backing up. I have now restored these items but the problem remains.
The shudown seems to occur at random, maybe after 1 hour or 10 minutes, and happens without warning.
I have noticed that on firing up the PC a Keyboard error the monitor shows the intruction to press Space bar to continue, although it will run through this if I don't. Also the PC bleeps occasionally during normal operation.
Any ideas please? Have I got a virus? I have run AVG and the results are negative. Thanks

 

[electronicsfreak]

download avg anti spyware and set it to delete on anything it finds

http://www.ewido.net

Im thinking you have a bad keyboard and need to replace it. But run avg anti spyware just in case. Do a full system scan with it.

There is a point in wisdom and knowledge that when you reach it, you exceed what is considered possible - Jason Schoon