You can try to go into the expanded menu (set focus on SETTINGS, then press >>,<<,>>,<<,GO) and run "start restore" under the maintenance menu. This will take you back to a prior version of the software. Then, when this process completes, you can try running it and see if it seems to be working correctly. If so (and you feel lucky) you can go to "update software", and have it upgrade your software to the current release.
Also, if you have any favorites that you want to keep, take note of them as it seems like software upgrades lose these.
You might also try disconnecting and reconnecting all the BS5 cables from the BM5, on the chance that this is just loose connection.
However, from what you describe, it is probably more serious than this...
Stan