My car won’t turn over

The anti theft system won't prevent the engine from turning over. If it won't turn over I'd be suspicious of the timing chain. A loose one can fail as you try to start the car and once it skips a tooth or two the engine won't turn over because the valves and pistons have collided with each other. That's only a guess though. Scan it for trouble codes. See it you can somehow turn the engine manually. If it totally won't move then something serious has happened internally. A few dollars spent at a shop with an actual technician looking at it can be money well spent. Make sure you know what you're getting into before you start spending more money on this car.