1993 Jeep Grand Cherokee

I just recently had my Jeep in the show for an all around tune up, it needed plugs/wires, battery, brakes, all the normal maintenance. While my vehicle was in the shop, the mechanic had told me that there were a few other things wrong with it, the radiator was leaking, so was the water pump. And that the PCM (I think that's what it was called) should be replaced, but I needed my vehicle to move, and couldn't wait for them to order the part. Within 2 days of being 800 miles away from this shop in my new home. My Jeep won't turn over. The lights are on, the radio works, even the heat works. But I can't get it to start. I called the shop and the guy told me he was positive it was the computer, but I don't think it is. What could be the problem? The battery is brand new. It makes a click sound when I try to start it, but then I let it be.
January 28, 2013.

If the click is when you turn the key to start, I would be looking at a faulty starter or a bad battery connection, start here.

Jan 28, 2013.