Here is a great article from OReilly Media about cleaning up your disk drives on Windows Vista. There are articles for other versions of Windows too. My computer had been running really, really slow and I was looking for some direction as far as getting rid of unnecessary files on my computer. This is one of the tools I used to do that. I also used Advanced System Care Ultimate 6 to uninstall unwanted programs and features, which has the added advantage of doing a registry scan for leftover bits of pieces of these files that often get left in the registry and just clutter up your registry and simply take up space.