Launch MSCONFIG by from the Run menu.
Click on the Tools tab. Scroll down till you find "Disable UAC" . Click on that line.
Press the Launch button.
A CMD window will open. When the command is done, you can close the window.
Close MSCONFIG. You need to reboot the computer for changes to apply.
** Note that you can re-enable UAC by selecting the "Enable UAC" line and then clicking on the Launch button.
More options here