The AV3100 has a problem with locking the entire screen when certain commands are learned, or are learned from certain remotes. This is probably what happened here. Sometimes the learning method affects this, so try holding the remotes farther away, or closer to, each other when learning.

If you have tried to clear the entire screen and it locks the remote, the only solution is a complete reset. Doing this will clear everything you have previously learned.

Before doing a complete rest, if you are planning to, try learning one command at a time on a new screen, and each time see if you can delete that command. Eventually you may find the command that is locking the 3100, or it may have just been a random occurrence, in which case it might be safe to try again.

Let us know how this works out for you.