Now that Marco has got you up and running, I don't know if this is useful information.
Andrew has described adding a text file safemode.txt to the bb\Preferences folder, then restarting. It will start with Factory Defaults.
Before doing that, though, save your settings under "Options".
Closing BIAB, creating an empty "safemode.txt" file using Notepad and then restarting BIAB could be worth trying. If it doesn't solve the problem, close BIAB and delete the file and then things will go back to normal once your reload your saved settings under "Options".
Regards,
Noel
P.S. Nice detective work, Marco!