I've been talking this sort of thing over in another thread, and thought it would be useful if I put a download link here. Revo Uninstaller is a great little bit of freeware that can clean your registry, cookies, temporary files and a load of other things. It's small in size and free forever (or so I believe), so you could definitely try it out. To date I've got no complaints with it.

Revo Uninstaller

If you've got any thoughts on it feel free to share them.