When I bought my 98 Disco 1 five years ago I contacted a dealer and got the original radio code from the service department and it worked until recently. Now when I enter the code that has worked before, the radio beeps on the final number but the word "code" remains on the display and the radio does not come on. If I turn it off and back on and try again it sometimes beeps on the 3rd or 4th number entered. I've disconnected and reconnected the battery but it didn't change anything.
Is there some way to reset or re-boot the radio so it recognizes the code again? Any suggestions will be appreciated.

EDIT: I found an older thread that said the radio had to be left on for an hour to enter the code again so I did that (put a charger on the battery while I did that) and when I entered the code it again beeped on the 5th number but the AM band came on, so I think I am back in business. I changed it to the FM band and scanned to the next station and I have radio again; I will try the CD player next.