My Go 620 was working fine. It told me there was a software update, together with an update to speed cameras and electric car pumps. I pressed the update button, as I’d done many times before. The unit seemed to download the updates, and then I got the TomTom Home Screen loading, with the distinctive chime sound, and the screen went blank with the little circle indicating something was happening, but nothing did. The circle just kept on going round. I’ve tried pressing the on/off button for long continuous periods, but all I get is the TomTom Home Screen loading, with the distinctive chime sound, and the screen again goes blank with the little circle turning around endlessly. I left it for over an hour, and when I came back it was still circling endlessly. Any suggestions?