My Desktop keeps going black, and closing active windows?

Concerning Windows XP (WHICH SUCKS)

My brother had a virus on his pc yesterday, and Avast detected it. he clicked repair and it said it had been repaired but after that the desktop kept flicking between the icons and blackness. Is there something wrong with Windows explorer, as when the screen goes black it closes all active windows so its hard to try to do anything. Is there anyway of fixing Windows explorer, is it corupt or something. Tried to repair from the windows disk at boot, but that seems more geared to fix it if you cant boot at all, and the stupid list of functions on Security console dont make any sense to us. Any ideas? All system restore points are gone to so thats out of the question Please help.

My Desktop keeps going black, and closing active windows?adware

Jobs knackered mate, you need to have it to a repair shop. Sorry.

My Desktop keeps going black, and closing active windows?antivirus scan

You can try calling technical support for your brother's pc, or you can try resetting the entire pc.
The two previous answers may well be right,but I would be interested to know if the same behaviour occurs in safe mode.Please try safe mode to stabalise the position.If you then make progress,I would suggest an online scan at http://housecall.trendmicro.com/