Don't forget to check for trojans. Not sure how likely it is, but worth a check anyway. Especially if appears to be semi-randomly rebooting.

I'd have to concur with the previous format suggestions. There's no telling what else could be hiding in there that you may miss, especially if these problems have been occuring for a while. It's probably best just to format and start over...lot alot can live through that. Then firewall tha bastard!! I'm an Norton fan myself...

alpha