Restart your computer and press F8 and select from the Safe Mode menu > Safe Mode with Command Prompt and press Enter. After the loading process is ready, type: net user (the name of the administrator account)/active:yes/. Next type: shoutdown -r and wait until the Windows complete the restart process. The administrator account will appear without a password.
Another method that can help you recover your administrator account password can be applied only if you have another guest account. You can use a program like Windows Password Key to help you recover Windows local administrator or user password and domain administrator password.