While working on several home computer systems that had corrupt user profiles I needed a way to get a valid login. Windows XP, Vista, and 7 all have a default Administrator account that is disabled and hidden from normal use. This account sometimes will become available in Windows XP systems in Safemode, however you may need this available in normal mode.
We fix system regularly and so we have a recovery CD that we typically use, Hiren's Boot CD, to enable the local Administrator account. The Hiren's Boot CD has an application that will both reset the passwords and enable the Administrator's account. However at the end of the repair process we need to hide that local Administrator account again to protect it in case it is needed again later. The simple solution to this is to use the following steps.
1. Open a command prompt as the local Administrator; right click on the Command Prompt and select "Run as Administrator".
2. Run the following command:
net user administrator /active:no
3. Exit the command prompt and reboot.
If you find that you have a login that is working but need to enable the local Administrator account, you can just use the /active:yes parameter.