We are switching from cable to streaming. I am installing my third Roku Express, the first two with no problems. This one connected with our wifi, updated the software, went to the display setting process, selected 720p -- but the HDCP button never finished grinding, and after a couple of minutes the screen went black. Several minutes later the screen came back to the same place with the HDCP button grinding again, same result. I'm stuck there. What's wrong?