hmm, ok, because if the courser is moving by itself, there's some kind of control/input issue, and I can assure you that it is not a bug that is native to the game itself.
I would suggest you back up all your important stuff (pictures, save games, homework, etc), format your HD and reinstall windows. Because there's some kind of system conflict (virus? other program?) and I'm not sure how to pin it down, unless someone else comes in with another idea.