As promised, freeware, open source & liable to lock you out of the house for the night if you aren't careful!
The source code, dlls & compiled exes are in the zip. There's even a ReadMe type file.
Make sure that you have an admin account that this is not running in!
I'd be interested in bugs, suggestions for improvements, posting of improved versions & feedback about which assumptions I've made about Vista (in which this probably doesn't work).
If it all goes pear shaped the registry entries are pretty obvious in the source code.