1998 Grand Prix GT security system..

Hi Joy, the keys and new ignition need to be programmed to the car so it can run. It has to do with the security system. You didn't need to replace the ignition lock, just have a new key cut and programmed. Contact a locksmith that works on vehicles and can come out and get you going.

TDolby is spot on. Once you get the new key programmed to the vehicle, you can program additional keys yourself. Here's how. Use the working key to start the engine. Shut off the engine and remove the ignition key. Immediately insert the next new key to be programmed and turn the ignition to the run position but don't try to start the engine. Watch the security light on the dash. When it goes off turn the ignition to the lock position then, without removing the key, start the engine. Up to 10 keys can be programmed to the vehicle. Hope that helps! Jim