Though inappropriate to ask here.. If your TV is like most of today's, should be able to access the more technical systems settings area, through a specific combination of physical and or remote button presses... In sequence..Try the following methods and hope it works out for you.

To enter factory mode: Open source menu, and then press digital button "3", "1", "9" , "5" in turns to enter the factory menu. Press ↑ and ↓ button to choose the item, press OK button to enter the submenu, press ← and → button to adjust the value.

To Leave factory mode: Press menu button to back to upper menu until leave factory mode. However, don't do this yet, cuz we want to factory reset. But always remember to safely back out of this area in future after making any other changes.

To factory reset: Enter factory mode, enter "SYSTEM SETTING" item, select "FACRESET DEFAULT" item and press OK button to reset the flash memory. TV set will restart when it is finish.

Good luck!