Car will not start

So when the key is turned, nothing happens? Does the theft light turn off?

If the light does not turn off then we have a security issue. You can try and put the key in the ignition on the on position for 10 minutes which may unlock the system.

However, if not, then we may need to scan for codes to see if there is an issue with the system that has disabled the ignition.

Take a look at this document which will explain this system in a little more detail.

Here is a guide that talks about how to check for codes:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Let me know if the theft light goes out and you still don't have any lights on the dash and we can try to figure out why there is no voltage to the systems.

Also, can you provide some background to the issue? Did this just start or has there been other issues leading up to this?