But of a weird one, today my late 2013 MBP Retina's screen has faded out to black while in use. It then does nothing for about 15 minutes before coming back to life. Weirdly, I don't seem to be able to shut it down (pressed the power button down for a solid minute, nothing), and it isn't responsive to anything I do. It has happened both when plugged in and unplugged (with 90% power). Any advice would be appreciated!