I just thought of this now.

My starter will sometimes clickclickclickclick... when I turn the key, and the engine won't start. Jumping it will (most every time) fix the problem.

I just got a new battery, and the old thing that goes on the negative post doesn't fit 100% tightly.

Could the lack of a good ground cause the car to not start, and then when it has cables attached, fix the ground and allow the car to start?

I have interior lights/radio/headlights when I am getting the clicking though. Does this mean it is the starter, and not the ground?

 

Hmmm..

Those were my exact symptoms before I got mine replaced. The contacts were almost worn off.. jumping it might help but obviously isnt a realistic solution.

Sounds like the starter to me.