Q: I have a 2007 Ford Taurus that doesn't crank or start and the anti theft light goes off when I turn the key

If the problem is simply no starter motor operation the fault is typically quite limited. With a fully charged battery that passes a load test, or a new fully charged battery as required, and the immobilizer (security) system off - check to be sure the immobilizer is not activated - if the starter motor does not operate (i.e., crank the engine at adequate RPM) at that point, there are only two possibilities: 1) either there is no power to the starter motor/solenoid, or an excessive voltage drop, hence the entire starter circuit would have to be diagnosed and the fault found and fixed; or 2) there is power but the starter/solenoid itself is bad and that includes intermittent operation which does happen. In scenario No. 2 the starter motor would simply be replaced. If you desire that a specialist from YourMechanic determine which of these is the issue, and get it resolved, please request a no start diagnostic. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.