My car will not turn over and start.

What is your question?

When I put my key in the ignition and turn the key, it tries to start, but will not turn over. It sounds like it's trying to and you could flood the engine because gas is going through. We've replaced the gas line and the altenator with no success. I also have had my aftermarket security system disabled because there is a light with a picture of a car and a key in the middle. ANd it still won't start. Any ideas what this could be? Thank you!