We've used our Roku Express for almost a year. Suddenly (no power outage, nothing came unplugged, etc.) the Roku has completely stopped working. The light blinks, but the TV screen remains black, with no input. All connections between the device and the TV have been checked and rechecked countless times. We've attempted a factory reset. The device is no longer listed in my Roku app as a connected device. When I try to connect it, we can't get a code because the TV screen remains black. The TV is working fine otherwise. Please help.