1. Start > Run > MSCONFIG
2. Click on the Tools tab.
3. Scroll down till you find “Disable UAC” and click it. (Choose “Enable UAC” if you want to enable it).
4. Press the Launch button.
5. A command window will open, and when the command is done, you can close the window.
6. Close MSCONFIG and you are done.

You need to reboot the computer for changes to apply.