Hyundai computer box

Hey guys I have just purchased this car it was stolen and recovered and the computer box is missing. I went down to the local scrap yard and purchased a new computer box, it came with two other boxes one silver and one black, a key and the ignition. All of these parts came from the same car that was accident damaged. I plug them all in, fitted a battery turn the key and the car cranks, but will not start. I have checked all fuses and they are fine. I am also getting good fuel pressure, but not spark from the plugs. Could anyone tell me why? PLEASE