Windows 7 (or Vista) has a hidden Administrator account, for some unknown reason [ok, fine, it’s to do with security features and not giving a regular account granted admin rights to change some things, admittedly, it’s a smart thing to do in general].
In some random cases, you may think that you want to activate this account, because you feel you should be able to view some files that you aren’t, because you want to feel the power beneath every keystroke as a true admin, or because you want to make some major changes to the Operating System.
Well, to change this it’s a fairly simple command:
First, you must open cmd prompt as an administrator, to do this, simply right click on the icon and select “run as administrator“. You will find this in start -> all programs -> accessories.
Now you should see your command window. Type:
net user administrator /active:yes
This will turn on your “secret” administrator account.
The start screen, when you log off, or reboot, will now have your account, and the account labelled administrator, as you wished for.
To then deactivate the account, it’s another fairly simple process. First, run command prompt as admin again, then type:
net user administrator /active:no
I suggest, if you do feel the need to activate this, that you do what you thought you had to do, then deactivate it again. Activating it this way creates certain security risks if you do not configure the password of the account, as well, having a user with admin privileges will work in nearly all circumstances anyways.
Reference: How To Geek