Just be very careful with any "computer maintenance software." It will often create a whole new set of problems.
Dunc's suggestion is more applicable than Microsoft would care to admit. The most fun arises when you re-install stuff and the same problems appear, which is what happened threee times with my soundcard. I had to find people who had already faught through the issues and try to apply some of their workarounds, because I'm not educated enough to do it myself.