Dodge Durango crew sometimes won't start or sometimes is hard to start.

What is your question?

I've had this car for a year and a half. Last year the computar module that regulates the voltage that my alternator gives out stopped working so the dealer replaced it, I had to replace the battery and alternator also. Flash forward 1 year later my Durango now sometimes doesn't want to start. The first problem occurred when I tried to start it and there was no crank at all, my radio worked and all my lights would come on all I heard was once single click, but it didn't happen all the time. There would be times where I could go weeks without it happing. Now it has a new problem on top of not starting. I drove it to the store and when I went to get back into my Durango I turned it the key and it wouldn't start no crank at all but as I was turning the key the dash board lights were flashing and the radio was also, I finally got it to turn over after about 20 seconds of it trying to turn over. What could be going on? I've taken it to 4 different mechanics 2 of them being dodge dealerships and no one can find out what's wrong. The one dodge dealership said I needed a new battery so I took the battery to the shop that I purchased it from and they tested it only for it to come back as good.