How to enable the hidden Administrator account in Windows 7 & Windows Vista via command line

Problem;
Unable to log into a PC running Windows 7/Vista as Administrator because the account is disabled/hidden

Solution;
Enable the built-in Administrator account by following these steps:

1. Click Start, and then type cmd in the Start Search box
2. right-click cmd (command prompt), and then click Run as Administrator
3. When prompted by the UAC click Continue
4. At the command prompt window, type net user administrator /active:yes and then press Enter
5. Log off as current user and login as Administrator Note: No password has been set on the Administrator account by default so be sure to set one
6. You can deactivate the Administrator account by typing net user administrator /active:no