Problems with insufficient privileges at uninstall is a very annoying problem in Windows 7. I have tried different scripts and codes to "regain" permissions on registry keys, but most of the time I end up having to do it manually. You can try using programs such as Ashampoo UnInstaller 4 or Cleanse Uninstaller Pro and there are others, but more times then not, I still had to do some manual work.
If it is a game, it is likely that it won't be that much work. If it's a heavy program like Adobe or Microsoft Office, make sure you have enough milk for coffee in your fridge.
WARNING: The following tip involves moderating your registry files. You should make a backup of your registry before proceeding!
In the warning message you...