Enable Administrator Windows XP home / Windows 7 Home

On Windows XP Home  edition you could need to enable Administrator account and assign him a password.

here are the relative steps to do:

1. Regedit --> HKEY_LOCAL_MACHINE | SOFTWARE | Microsoft | Windows NT | CurrentVersion | Winlogon | SpecialAccounts | UserList |

  "New" > "DWORD", rename it "Administrator" with value 1.

Then give command:

net user administrator /active:yes

otherwise:

wmic useraccount where name='administrator' set disabled='false'

2. Error Message: Unable to Log You on Because of an Account Restriction

http://support.microsoft.com/kb/290109/en-us

The Administrator account is not displayed in User Accounts unless the 
computer is in Safe mode. To change the password for the Administrator 
account:

1. Click Start, click Turn Off Computer, and then click Restart.
2. After the computer completes the Power On Self Test (POST), press F8, and then click Safe mode.
   
   NOTE: If you have difficulty getting to the Safe mode menu command, press F8 repeatedly after you turn on the computer.
3. Log on as an Administrator, or with another account that has Administrator permissions.
4. Click Start, click Settings, click Control Panel, and then click User Accounts.
5. Click the Administrator icon.
6. Click Create a Password or Change my password.
7. Type a password for the account, and then retype the password to confirm it.
8. Type a hint to help you remember the password in the event that you forget it.
9. Click Create Password or Change Password.

For additional information about how to create and configure user accounts in Windows XP, click the article number below to view the article in the Microsoft Knowledge Base:

279783 HOW TO: Create and Configure User Accounts in Windows XP

On windows 7 Home you need:

1. Start the command prompt (cmd.exe) with admin rights [1] and run this command [2]:

net user Administrator /active

[original article http://www.windows-commandline.com/enable-disable-administrator-account/ 

http://www.azpoint.net/consigli/windows/11694/Windows-XP-abilitare-Administrator-al-logon.asp]