Will not start

I have replaced the alternator and spark plugs and it will not do anything at all until I give it a jump and even then it will not turn over, just cranks and clicks. Someone told me I need a new distributor cap or something. When I called AutoZone and Advanced Auto Parts they told me my model vehicle is not built with a distributor cap. So now I am stuck in a bind. If I can just figure out exactly what is wrong with it, I can pay to have it repaired. But I do not know much about cars. Can someone help me out please?