Gene,
A couple of thoughts spring to mind. Before jumping into the complex options, though, try this and see if it helps...
1. Make sure BIAB is closed.
2. Unplug any music-related USB hardware (e.g. MIDI keyboard, etc.)
3. Right-click on the start-up shortcut and select "Run as administrator". (This is starting BIAB in Administrator mode. It is different from logging-in into Windows as 'admin' when a computer is first started. "Run as administrator" is the mode that's recommended for BIAB and RB.)
Does that bring any joy?
Also, after installing build 516, it's necessary to rebuild style picker. To do this, simply enter into style picker, wait a few seconds and the process will begin automatically. It should take around 30 seconds or so to rebuild.
Regards,
Noel