Update: This should also work on Windows 7, 8, 8.1, and probably 8.2. It’ll also work on Windows 10.
Note: Disabling UAC will lead to a less secure system, so be warned.
Windows needs your permission to annoy the crap out of you:
There’s a quick way you can enable or disable this annoying window from the command line:
Disable UAC
Enable UAC
After you enable or disable UAC, you will have to reboot your computer for the changes to take effect.
You can also enable or disable this from the Control Panel if you choose.