My xbox was not turning on. Unplugged the power supply, waited for the light to go off, plugged it back in and nothing. I unplugged everything from the console (power supply, HDMI cable, ethernet cable, Kinect, and external hard drive). Only plugged in the power supply and it fired right up. Plugged everything else back in and when I got a picture on the TV it said the console needed to update. I started the update it and the xbox turned off after the initial download. It did not turn back on. I unplugged only the external hard drive, pressed the power button on the console and it turned back on. I left the hard drive unplugged and finished the update. The console restarted two more times per the update and it was successful. Once the update was complete I plugged the hard drive back up and turned the console off. I turned it back on with the controller and it turned back on with no issues. Hope this helps.