First off, if you're not sure what to do in the registry or how to find it, maybe stay away from it or have someone more knowledgeble do it. It's easy to screw up the registry, so beware...

That was the disclaimer... You'll find uninstall-information either here
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Uninstall
or here
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall

Stig