If you forgot your password or lock screen combination it's very easy to format your phone and get the original factory settings.Just Follow this steps"
1.Power off your phone
2.Press together with left hand volume down + power button
3.When the led of the bottom of the phone lights on,touch and hold the menu key with your right hand
4.When phone vibrates release power button
5.Release all the keys of the phone before Lg logo disappears
6.Wait until the phone restarts