1. Press Windows Key + R. to open RUN Box
2. Type “control userpasswords2″ and press Enter.
If UAC is enabled, then you’ll get a UAC prompt on screen. Please specify credentials or permission to pass the UAC elevation.
3. Select your account from the list.
4. Uncheck the “Users must enter a user name and password to use this computer. “
5. Click Apply and a dialog will appear (See Figure image).
Enter you password for required user and hit OK, this should now enable Auto logon of selected user to WIN7 PC.