The same is the case with the default administrator account. If the Guest account is the “Built-in account for guest access to the computer/domain” the Administrator is the “Built-in account for administering the computer/domain.” Now the administrator account is not only disabled by default such as the Guest account, but it is also hidden.
In order to enable it and bring it to the surface enter “cmd” in the Search Box integrated in the Start Menu and right-click the Command Prompt icon that will be displayed at the top. Make sure that you launch the process with elevated privileges via the Run as Administrator command.
In the Command Prompt windows enter “net user administrator /active:yes” in order to enable the Administrator account. If at any time you change your mind and want to revert to the original settings, then type “net user administrator /active:no” and hit enter. The built-in Administrator account will show up just like all the other accounts when you will log in, but it will have absolute power over Windows Vista and will not be limited by the User Account control.