My Son had a problem with his Nexus 7, it wouldn't turn off or turn on. It just hung with the Nexus cross on the screen. I followed information regarding the re-seting by holding down the power button and the volume button and got the little Android robot up. I tried "powering off" but this just turned the device off. I then tried another option that I think was something like "Reboot" (but not sure!!) and the tablet went off and I can't get anything out of it now. Please help as I have a very upset son!