Car won't start

When I put the key in the ignition, and turn the ignition to start the car, it won't turn over. It makes a noise as if it wants to start but won't start. I've had this problem several times, always when I park the car in my driveway which is inclined, engine facing up in park position. Several times, when this has happened, I've moved the car with the engine facing down hill in park position and it would start up after a day. This time, it wants to start but won't kick over.