It was working fine yesterday and I switched it off overnight as usual. When I switched it on this morning it refused to boot up. It sticks on the Android screen for about 20 seconds, clears the screen for a couple of seconds then the Android screen for another 20 seconds and so on. Removing and reconnecting the battery makes no difference. The usual Android trick of holding "Volume Up + Home + Power" simultaneously to go into safe mode has no effect. Anyone any other ideas?