How can I unlock my remote?

Does anybody know how to unlock my remote control? I have a 20" ONN LCD tv and I pressed something on the remote by accident and now the TV is froze and will not respond to the remote.The TV comes on but there is no sound and it says "MATURE" at the top of the screen. The remote is working because when I press the buttons the sensor light on the TV flashes but nothing I press works. I think I have somehow locked the remote and I have tried everything to unlock it but can't.Any ideas?