Enable the (Hidden) Administrator Account on Windows 7 or Vista

Found the trick here:  http://www.howtogeek.com/howto/windows-vista/enable-the-hidden-administrator-account-on-windows-vista/

First you’ll need to open a command prompt in administrator mode by right-clicking and choosing "Run as administrator” (or use the Ctrl+Shift+Enter shortcut from the search box)
Now type the following command:  net user administrator /active:yes
You’ll note that there’s no password for this account, so if you want to leave it enabled you should change the password.

To disable:
net user administrator /active:no