Activate, Enable and Show Administrator Account in Vista Welcome Screen

Windows Vista has built-in administrator account that is disabled and hidden by default, just like Windows XP (see how to show administrator account in XP). But unlike XP where any normal user account designated as Administrators group will have the same privileges as administrator account, in Windows Vista the administrator account is true super user account (equivalent to root in Unix/Linux). Obe advantage or benefit for using administrator account to login to Vista is admin is not subjected to UAC (User Access Control) restriction (see how to disable UAC).
How to Enable and Activate Administrator Account in Vista and then Unhide or Show in Welcome Screen

To activate the administrator account in Vista, follow these guide’s instructions:

1. Logon to Windows Vista with normal user account username and password (must belongs to Administrators group).
2. Click on Vista Start button, and type cmd in the Start Search box.
3. Right click on the Cmd returned on the search results pane above, then select Run as Administrator.
4. In the Command Prompt window, type the following text at the command line to set a password for administrator account. If you want to use a blank password for the Administrator account, skip this step.net user administrator passwordReplace password with the actual password string that you have chosen. Press Enter when done.Note that if your computer is a member of domain controller or has enabled complex password requirement in Local Security Policy, you will have to pick a really hard to remember password mixed with symbols.
5. Next type the following command and press Enter to activate and enable Administrator account:net user administrator activate:yes
6. The process should completed with the following message:The command completed successfullyIf not success message is returned, repeat the process again.
7. Logout from Vista by choosing Log Off or Switch User.
8. Click on Administrator icon and logon with the password you selected.

You can also enable Administrator account via Vista GUI.

Src: http://www.mydigitallife.info/2007/08/10/activate-enable-and-show-administrator-account-in-vista-welcome-screen/

However the article above is not working for all Vista, and unliuckily it didnt work for my new HP notebook- so here goes another way for HP Home Premium licensed users-

net user administrator /activate:yes

Now either “Switch user” or “Log off”. You’ll see the Administrator login link. Now a little more to go, you need to set pass for this account, so what you have to do-

1. On Start > Search box type “CMD” and hit enter
2. Wait! don’t hit enter again!
3. Right click on the CMD link and select “Run as Administrator”
4. Command shell will be opened
5. Now type the following command to put password for Administrator account-

net user administrator password