I have set up and used my Roku for the past few weeks without issue, but now all of a sudden it has stopped working. The device is plugged in to an outlet and the white light is on. It is also plugged into the back of my tv via HDMI cord. There is a connection, but even though it is on the correct input, my tv is not acknowledging it. I just get a black screen. No home screen or anything. I have tried doing a factory reset and taking the batteries out and changing the outlet. No luck. Please help!