Can any good experienced mechanic give me an advice?

I have a Dodge Stratus 2002 I bought a month ago and it already started giving me problems. It was all fine for like the first 2 or 3 weeks until one night I got off from work that I went to put some gas. when I turned the car back on it started doing a clicking sound and killed my battery. So I replaced the battery. Then I thought It was the starter so I spent more money on the starter. Then I called the guy who sold me the car and said that It was the alternator. So I went to Auto Zone for diagnostics for my car and everything is good including the alternator. So now once I use my car and I turn it off, I can't turn back on right away cuz its tarts doing the clicking sound again. the only way I can drive my car is when the care cools off. So somebody told me it could be the computer that heats up and don't start until it cools off... Can any one tell me if that's the right reason?...I would like to have a good advice from an expert or a good mechanic.