Low Battery light came on on the dash, so I took the key to radioshack an put in a new battery a couple of days later. Just tried it and nothing works. Do I have to reprogram the key at the dealer?

 

Low battery light on your dash means that there's a problem with your charging system. Try to check the alternator if it is producing the proper voltage and current.

 

Sorry, I was not clear on this. The dashboard warning said "keyfob battery low" that is why I replaced the battery for the key. The problem now is that the buttons to lock and unlock the car do not work on this key. The other key works fine.