Just had this happen after a power surge from a major storm. After searching and searching for a solution, we found a video that helped.
unplug the roku from electrical outlet. Insert toothpick or paper clip into the very tiny reset slot on back of roku next to the power cord slot. Hold that paper clip and press for reset while at the same time reconnecting the power cord right next to it. Hold that reset for at least 10 seconds. This was a two person job for us. One holding the reset and one reconnecting the power.
hope this helps. Worked for us after wasting many hours trying to reconnect.
