Your key actually has electronic circuitry inside the
black plastic handle...

Somehow your security system is not recognizing your key... recently dropped, laundered, drowned... damaged in any way:

Your best, only & cheapest option to get your car
running is to try the other key...


If it gives the same result ...
The transponder is the fault...

You can begin looking at this circuit by going to BBB Industries
(registration required: see below)

BBB Industries Premium Alternators Starters Power Steering Products

Problem with theft system ,anti-theft . Is security light lit on the instrument cluster ? Anti-theft will cut off fuel injectors is it see's a problem . you best bet have towed to a GM dealer . Nothing your going to be able to do .