Frigidaire In Wall Oven panel showing Err F11

Hi:

Oven continuously beeps; rarely takes input from keypad - even to set the clock. Occasionally stops beeping when you hit the start button. Will not heat or do anything. Powering off, trying to lock and unlock provides no solution.

Any good ideas on how to resolve this/ The oven was manufactured in June of 2008 and has been used once or twice.

Thanks

Bob