The horn goes off by itself. The car won't start, but all electric works. on 1997 Volkswagen Jetta

The '97 has a factory security system that goes off by itself. Unlocking the car by key shuts it off. Futhermore, the car has stopped cranking up. All electric still works fine. It has a new starter and battery.The starter won't even tick when the key is turned. What else could cause the car not to crank?

Asked by for the 1997 Volkswagen Jetta
This looks to be related to the security system. I would take it to a repair shop that specializes in VW and have them check the diagnostic trouble codes for the entire vehicle and diagnose accordingly.