One of the problems with uninstallers is some programs replace DLL files that you need with their version. When you uninstall, they are not sure what to do about these files so they leave them alone. In some cases that DLL may have even been modified by another program since your install so simply putting it back to what it was might kill the newer program you aren't uninstalling.
The joys of windoze huh?
I really like totally self contained programs like Paint Shop 4 and Agent that don't need to be installed. They just run as a clean EXE and go away when you close them. That is the way it used to be before W98 and some guys still write code that way.
