This is what I've done twice now when it's stopped working: unplug the power cord, hold the power switch for 20-30 seconds (for some reason this part seems to be the most important part), plug the power cord back in, hold the power button again until you get the prompt to plug the USB cable into your controller and then check for an update. Both times it seems I was missing the latest update. So it installs and then rebuilds the database. After that it works. (When I've tried to do this without unplugging the power cord first for 20-30 seconds it doesn't seem to work, so unplugging the power cord is key.) Anyway. Hope that helps!