I tried all these things and none of them worked. I then found a solution . So, if these fixes don't work for you, try this. Take the back off your nexus. Disconnect the battery and then reconnect. Plug the Asus charger into the device and try turning it on. I immediately got the Google logo and it booted up. As there was 0% charger it soon powered off but then the magical battery charger symbol appeared. After charging for a few miss I turned it back on and all works fine.