2000 Jeep Cherokee Not starting

My Jeep was running great until one morning a week ago it would not start. It would turn on and everything would work - radio wipers lights ect. But it would not start. My dad and te gut next door said it sounds like the fuel pump. I had it towed o\to the local daealership where they orders a new pump. Te pump was installed and they call and said that it was not the pump it was the PCM controler. I asked what that was and they said that it was the electrial mother board of the car. I asked what would fry it he said that is a mystery. They order a new one and now they are saying that it is a crank shaft sensor that fried it becuase of something with the new one was out of wack. Now my car is costing me thousands of dollars. I would like to go back to the PCM if this is the brains of the electrical system what happens to my jeep if it is fried? Wouldanything work - I am tinking along the lines of a computer if the motherboard is fried the computer would not start at all - is this the same for a PCM?

I think that I am getting hoses from the dealers ship and I need some answers besides what they say.