Once in a while, I run a defrag across the computers (using defraggler of course!). Before defragging, one should run ccleaner to clean up the drive first. However, it only cleans up the files of the currently logged in user. Example, i log in as administrator, run ccleaner, and it will clean up all "documents and settings" for administrator, but NOT User1, User2, User3, etc.
IMO, it should, or there should be the option to, tidy up ALL profiles on the PC. (Rights depending).