I have an xbox 360s which is about 15 months old, today it wouldn't switch off using the touch pad so had to switch off using controller. tried switching back on but would only work by opening and closing disc drawer. console then switched itself off and then back on a couple of times. Console then switched on and was able to play game for a couple of hours, so finished game and switched off console. the power brick was plugged in and turned on, the console then suddenly started switching itself on and off repeatedly so i turned it off at the plug. Can anyone please help as to what the cause is ?