In the run menu type control userpasswords2.
Just press WIN + R to get the RUN menu.
The user accounts windows will now open up.
Look for the option saying ” Users must enter a user name and password to use this computer ” and uncheck this option and press “OK”.
Now a windows opens up asking you to enter the current password you use to log in to Windows 7. Enter the password and confirm. Done!.
From now on when you boot to Windows you will not be asked or prompted to enter the user name and password.