Trouble with Smart Key 2006 Prius

Hi Everyone,

I have a problem with one of my Smart Keys. Car was purchased used with 2 smart keys one of which had a lot more wear than the other. One is working just as it should. The worn one stopped working except when it is inserted in the dashboard key slot. I replaced the battery and now the red LED flashes with all 3 buttons; however they do not Lock, Unlock, or Panic anymore! Car does not respond at all! I have read that the keycode is unique to the key fob and that code ought to be already accepted by the car. What do I have to do to get this key working again? I am getting a new aftermarket shell and plan to make the key look better and replace the missing red button.