You could reflash the firmware with a copy from a normal kindle DX (preferably another one that you own, or from a friend or relative). You would need a serial cable to do that. Details can be found in the developer's corner forum. It would still have the old serial number, which can be changed too, but only a valid serial number can be registered.
It would take some study and experimentation on your part to learn how to do this. Just because it can be done does not make it worth your time to do it. You have to decide whether to spend your time learning how to do it, or to spend your money to buy another one that already works. It all depends on how you value your time.
Last edited by geekmaster; 05-29-2012 at 12:36 AM.