4 methods to enable Built in Administrator account in windows 8 , Windows 7 and vista

Microsoft has recently released the Developer Preview of windows 8, However , like the previous versions of windows ( Windows 7, and vista ), there is a built in administrator account.But it's not enabled by default.I'll be explaining 4 methods to enable it.
NOTE:The methods below start by elevating a run command. you can start them by just typing the command in the start menu box or ....start>run>   or using the keyboard shortcut (win key + R) to start the run box.

Method 1 : Computer Management.
1 - Run compmgmt.msc