A hard reset, also known as a factory reset or master reset, is the restoration of a device to the state it was in when it left the factory.
All settings, applications and data added by the user are removed.
The term is often heard in reference to smartphones and tablets but laptop and desktop computers, as well as most other electronic devices, can usually be restored to factory conditions.
1. To begin the operration use your power button to turn OFF the device.
2. Now press combination of Volume + Quick + Power Buttons and hold them untill next step.
3. When LG logo will appear on screen release both buttons.
4. Device will now restart itself and in few minutes you will be able to work on your phone again.