Last week, I had a few difficulties with defragging, (see my thread) and used a combination of CrapCleaner (Free) and Diskeeper (trialware, but I will now be buying it) which has perked things up no end. It has given me a much more responsive machine.
Conan
PS Did the same for a friend's daughter last night on her laptop. Fullly expect happy faces when I see her later on.