How to Disable
The enhanced security considerations notwithstanding, UAC is by no means essential for the computer to run, and some users may want to disable it. There are many ways to disable UAC. The two common and easiest ways are from the control panel and using MSCONFIG.
Open control panel and type 'uac' in the search box. A link appears under 'User Accounts' saying 'Turn user accounts Control (UAC) on or off'.
Alternatively, browse to 'User Accounts and Family Safety' ->'User Accounts'-> 'Turn user accounts Control (UAC) on or off.
When another UAC pop up appears, click on 'Continue'. A dialog box appears with instructions on how UAC protects your system and recommendation to keep it enabled. To disable it, just uncheck the box 'Use User Account Control (UAC) to help protect your computer" and click 'OK'. Vista will prompt you to restart your computer for the change to take effect.
Open the Run menu and type ' MSCONFIG'. The MSCONFIG windows appears. Navigate to the 'Tools' tab and from the list of tools select 'Disable UAC'. Click on launch. A command window appears with a message 'The operation completed successfully'. Close the window and restart your system.
A third option to disable UAC is by editing the registry or using the group policy editor, but these methods are best left to experts.