Keyless Entry and remote entry quit working

[crc443]

I have a 2002 Ford Explorer. Today the keyless pad and the remote quit working. I was able to get the remote re-programmed but it has quit working again. When I press the 7/8 and the 9/0 buttons together it still locks the doors but the factory code will not work. Lights on the keypad work for each button. Any help will be greatly appreciated.

Thanks