wont start

What is your question?

Saturday night my car started to stall out when I arrived at my parking lot and turned off the car it wouldn't start again. We changed the cam shaft thinking that may be the problem again but that didn't work. We had the starter tested came back in poor conditions so we bought a new one, but that didn't fix the problem either. The radio, and lights work but the only sound the car makes is a clicking sound. What could be the problem