I've been having this problem for some time now but I never had a clue about it. My C directory, which is quite filled (about 10Mb left...) keeps changing the free space that is left. It goes from 10mb to 6Mb in one second while I am not doing anything. And even when I'm trying to free some space, it still goes down. Is this a virus? And if it isn't, what can I do?