2000 Grand Prix gtp won't start

I just did an engine swap on a 2000 pontiac grand prix gtp 3.8L s/c. After getting engine in we try to start the car but it would just turn over and wouldn't start. We checked the fuel lines and they seem to be getting fuel fine. Next thing we checked was the plugs for spark. There was no spark at all so we changed the crankshaft n camshaft position sensors with no change. I don't think it is the ignition control module because we didn't change it and before the original motor locked up due to blowing a piston it worked fine and spark plug wires are brand new. Will most likely have to change spark plugs after I fix the starting problem but as of right now it is pointless be there is no fire whats so ever coming from the coil packs. Last thought I had come up with was the security system was active but once checked thoroughly it is not that. I have been told by a couple of people the computer could be the problem. Is there a way to test that theory without finding a new computer for the car or a way to reprogram it that doesn't consist of me bringing the car to a dealership. Or if you have any other opinions on what it could be any and all help is appreciated.