I had the issue of my ZenPad not charging after a small drop. Also the home button stopped working. When i tried to power up, a low battery icon appeared briefly but nothing happened. Hard resets did not work. The reason in my case was a disconnected ribbon cable inside the tablet and was quite easy to put right. You need to take the metal back off the device, first make sure the sd card tray is out, and remove the 2 little screws either side of the usb port. Then use a prying tool or similar (I used guitar plectrums) to ease the screen and metal case apart. It comes off quite easily once you get started, just take your time. Once the back was off it was immediately obvious that the left hand ribbon cable was unseated from it's port. once the connection was restored, the metal case clipped back on and everything was working again.