Press the power button and when it gives you the option to turn the phone off or restart, press the restart option let it restart and that should fix it if that doesnt fix it you need to pull tha battery out for 30 seconds and place the battery back in power up the phone and that should fix it also same method works also for camera fault and several other faults for the phone this is not just for lg phones its standard procedure for all mobile phones before a factory reset