In previous versions of Windows, a built-in Administrator account was automatically created with a blank password, which is a security risk. So you can log on to Windows system to reset Windows 7 password when you forget the password. To better protect the system, the built-in Administrator account is disabled by default in all clean installations and upgrades of Windows 7.
For upgrade installations, the built-in Administrator account is kept enabled when there is no other active local Administrator on the computer. However, the built-in Administrator account is disabled by default for new installations and upgrades on domain-joined computers, regardless of whether there are other active local Administrators on the domain-joined computers.
Enable the Built-in Administrator Account
Change the properties of the Administrator account by using the Local Users and Groups:
Step 1. Open the MMC console and select Local Users and Groups.
Step 2. Right-click Administrator account and select Properties. The Administrator Properties window appears.
Step 3. On the General tab, clear the Account is Disabled check box.
Step 4. Close the MMC console. Administrator access is now enabled.
Or you can change the properties of the Administrator account by using the Command Prompt:
Step 1. Start System and press Ctrl+Alt+Delete to enter Safe mode with Command Prompt.
Step 2. Choose Administrator and you will enter the elevated command prompt, type "net user administrator /active:yes" and press Enter.
Step 3. Close the command prompt. Restart the computer and you will now see the built-in Administrator account log on icon added on Screen. Then you can add a Windows password to protect your computer.
Disable the Built-in Administrator Account
Original equipment manufacturers and system builders are required to disable the built-in Administrator account before delivering the computers to customers. Here are some tips you can have a try.
1. Run the sysprep /generalize command. If you run the sysprep /generalize command, the next time the computer starts, the built-in Administrator account will be disabled.
2. Use the net user command. Run the following command to disable the Administrator account: "net user administrator / active: no". Then log off, and you will now see the built-in Administrator account log on icon added (enabled) or removed (disabled) from the log on screen.
Now you can enable you Windows 7 built-in administrator account. When you forgot Windows 7 password, you can reset Windows 7 password with this account. There is no need to reinstall or reformat anything.