Hyundai Sonata EF 1997

If it starts then shuts right down then the anti theft system is active, try running the shut down procedure listed in the owners manual, but usually if it is in full lock down like this then the dealer will need to do a reset on the security system. Sometimes a smart locksmith has the equipment to also do this but not all of then can.

I had the same thing happen to my VW 2 months ago. It was a defective throttle body. But that's not saying that the anti theft is not on. good luck