UAC or User Access Control is a new feature of Windows Vista that is meant to enhance the security of your system. Each time an application is installed or whenever an important system change is made by the user or by a running process, the screen is blacked out and temporarily disabled and a dialog is shown with the choices to allow or deny the action. If the logged user is not an administrator, Windows Vista will also ask for the administrator password. While this helps keeping your system safer from threats, it can also be very annoying and sometimes confusing. UAC does clearly improves the security on Windows Vista, under some scenarios you might want to disable it, for example when giving demos in front of an audience. Some home users might be tempted to disable UAC because of the additional mouse clicking it brings into their system, however it is recommended not to immediately do so, and try to get used to it instead.
There are a few ways that you can use to turn off the UAC.
Click Start and then open Control Panel, now click User Accounts and Family Safety.
Select User Accounts, now click Turn User Account Control on or off, clear the tick or check mark on the box beside the Use User Account Control (UAC) to help protect your computer option.
Now click OK. When prompted, restart the computer. Note that the changes will affect all users on the computer.
To enable the UAC, simply tick or select the checkbox again.
UAC can also be turned off using registry editor:
Run Registry Editor by typing regedit in Search box(Start Search) in Start menu and navigate to the following registry key:
Locate the following DWORD in the right pane: EnableLUA.
Double click on EnableLUA to modify the setting. On value data prompt window, set the new value to 0.
Exit from Registry Editor, Restart the computer.
To enable the UAC again, simply change back the value of EnableLUA to 1.
Run System Configuration Utility by typing msconfig in the Search box(Start Search) in Start menu, now in System Configuration window, click on the Tools tab. Scroll down and select Disable UAC option.
Click the Launch button, command prompt window will open and automatically execute and run certain process to disable UAC. Close CMD window when done.
Restart computer for changes to apply and effective, to re-enable UAC, simply select Enable UAC.