My SC-HT920 has started to say on the display LOCKED. I am not entirely sure how it happened although I do have kids. Anyway, the device will not let me change to different DVD trays nor will it let me change any of the settings or anything else. It will not even let me eject the DVD's and it is totally frustrating - can someone give me any ideas of what may have happened. It will not let me get into a menu screen, so so so lost. Thanks.