Try a deeper reset. Plug the Kindle into the charger for 30 minutes. After that AND WHILE STILL PLUGGED IN, press or slide and hold the power button for 30 seconds. After that, try using it. Let me know the approximate purchase date if it still fails to function.
We may have resolved it. Charge it for another 30 minutes and try again. Let me know if it still doesn't work.
You can replace the battery if you wish and still keep it registered to your account. Up to six devices can share one Amazon account and all the books in the library. Let me know if you decide you want to do this.