Step 1: Press the home button on the TV remote to display the home screen and select SETTINGS
Step 2: Under Settings, select the SYSTEM
Step 3: Under SYSTEM, select ADVANCE SYSTEM SETTINGS
Step 4: Select FACTORY RESET and FACTORY RESET EVERYTHING
Or
Simply use the RESET option (a pin hole) on the back of the TV which is located just above the HDMI port. Use a pin and press & hold it for 30-60 seconds for the TV to Reset and Restart