If you did register the Kindle, you have the registration file on your Kindle already.
That sounds like a strange collection of problems to be having -
PLUS it is a used device with unknown history.
I would start out by re-installing both the Main and the Diags kernel-image pairs taken from the Debricking sticky thread.
I.E: Start clean because you don't know what all was done to it in the past.
You might even find that the hardware is not as broken as you think.
