What could be causing my car not to start?

What is your question?

My car wont start it turns over but won't crank . first time it broke down wouldn't stay cranked I took it home parked it and had mechanic come look at it at first the machine showed ignition switch needs changing , throttle body sensor is bad and needs engine coolant , I changed the throttle body and the mass airflow sensor the check engine light was still on so I put it back on the machine in now it only shows the engine coolant , so I tried changing fuel pump because a mechanic said fuel not pumping to engine and car still won't crank somebody help me plz?