Merlin Dobe

I have major engine code troubles. the dash display shows every code possible. engine derate, low fuel, tire pressure, traction control lights are on, ABS light is on. Windows do not work. only tach and speedo are working. I replaced battery it now at least runs, prior to it only ran for a few seconds and shut off. the horn came on by its self briefly as it was running. My scanner says not connected to module. I replaced the BCM checked all BCM fuses. All grounds are good, I tore apart the car to be sure. help??