new key problems

thank you first ill have the correct key made then i can go from there. the locksmith said this key is the one for the car. i did notice the security light go on, so i guess if i get the right key from GM i'll try your method. my key does have some numbers on it.PK.3 over the letter M. i dont know what this means.

If you got it from a locksmith I would think it is a transponder key that just needs to be programmed. A locksmith would know that I would think. However if I'm wrong, which has happened once before, you can definitely get the right key from the dealer.

I’m having trouble programming a new key without the old key to a Pontiac Grand Prix 08