I have an f-250 superduty power stroke 4x4 year 2006 For some reason it won't start, I turn the key and it turns over but won't crank ! Any ideas of how to fix this problem?

With an engine that will not start, first thing is to verify that you have fuel and spark.

Check your batteries. More than likely you are not getting enough amperage to start your engine. Charge your batteries and then crank it. If not then check your alternator, it might not be getting the charge to your batteries.

The batteries are brand new ! It was working just fine cranked up normally then I came home and parked it for a few hours then when I was ready to go out again I tried to crank it but wouldn't start! It had done something similar before when I was in traffic and it just shut off in the middle of the road and wouldn't start either! I had it fixed and they said it was the dummy plugs and some module , the ipr and that cost me well over two thousand to fix! I just hope it's not the same thing