Key will not start the car but all lights and radio come on.

What is your question?

When I purchased the car the car dealership could not find the key so they had a locksmith come out and rekey it. Now the rekeyed key has been lost but the original key was found. When put the key in it turns on and lights and radio work but will not crank the car. Is there something I can do to get the key to work again to start the car without having to call a locksmith?