Theft light comes on when I turn the key to the run position?

The theft light comes on when I turn the key to the run position, the theft light comes on, which never happened before. It’s not blinking, just solid, but it’s pretty bright. This, combined with the fact that there’s no spark to the engine, or signal to the starter, makes me believe that the anti-theft system has been triggered, and that it is preventing my car from starting. Can you please advise me as to how to correct this issue?