Access Menu on JVC Model AV-32430?

Bought TV used, menu function never worked on remote, accessed menu from TV, am now locked out of menu completely (because I locked the front panel on accident), and a big black square (close caption box) is filling screen. Not able to watch tv at all. How can I unlock the front panel button to access the menu again? can't find a reset button, tried a different remote, nothing works so far.