Uninstall function only removes GUI portions of the program. If you want to remove the entire file, you will have to go into the registery to do it. Windows XP has an interface that allows a search of the registry and makes doing this process very easy.
I come from an IT background and suggest that if you don't have a diploma from "Geek university", you might consider simply backing up all the files you never want to lose on to a external storage device. Then place you recovery disc from your PC survival package from the manufacture.Then run it. This completely restores the entire C:Drive. Meaning you will have to reload every software program you loaded after you purchased the PC. This is a drastic act, but does clean out the files from the system. I have never had a problem afterword and in fact discovered in most cases the PC runs better because you get rid of a lot of internet crap like spy ware.