The permissions under the following registry need to be reset:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windo ws\CurrentVersion\Setup

1. Run regedt32
2. Navigate to the key
3. Click on Security and then Permissions and make sure the following accounts have the correct permissions:
Administrators | Full Control | This key and subkeys
Power Users | Full Control | This key and subkeys
System | Full Control | This key and subkeys
Users | Read | This key and subkeys