1999 Plymouth Breeze 2.0L engine wont start

1999 Plymouth Breeze 2.0L mileage: 60,000. My car was running good until I decided to "fix" it. I had to do something my radiator was leaking badly due to some minor left-front end collision damage. I couldn't afford a mechanic, so I decided to do it myself. Since I've worked on several cars over the years I thought this would be easy. Little did I know how much fun was in store for me. I removed the radiator without too much difficulty. I had to disconnect the air conditioning components and automatic transmission lines. I went to the junkyard and obtained an exact replacement that is known to be good. I replaced the radiator. Once again, I didn't have too much difficulty with that. Everything connected with no problems. I replenished it with water but did not refill the Freon in the air conditioner. I did not have any ATF+3 transmission fluid to refill that but I thought the engine would at least start at this point, so I tried it. Not even a hit. It cranked and cranked. I went back and double and triple checked my connections and could find no problem. At this point I suspect I have tripped some sort of automatic shut down electronics. I bought a service manual from the parts store. After studying for about thirty minutes, I believe the ASD relay is stuck or bad. I get my multimeter and check the relay's coil resistance to 75 ohms which is good. I checked the n.O. And n.C. Contacts both fine. Next, I check the voltage supply to the relay at the relay connector block. I had no voltage. I Pulled the other three relays and check their voltage. They all have the 12V I was looking for. No voltage a.K.A. Fuse! I check the fuses and fuse number 5 under the hood is blown. It is supposed to be for the ASD and the computer a.K.A. Power train control module. I went to the parts store again and return with 20A fuses. I replace it. Fuse blows! I get out my meter again. I measure 12V on one side of the fuse and 0V on the other. Suspecting a bad computer but not knowing why since the engine ran fine before my radiator change. I disconnect the battery and remove the computer. I disconnected the two cables from the unit and replaced the fuse with another new one and connected the battery. The fuse did not blow. I'm not sure whether the computer is truly bad or one of the circuits connected to it. Do you think the computer is faulty and how do I prove it? Or, is it possible that some sort of trouble code is stored in the computer which would not allow the engine to start? Why would the fuse blow with the computer in-circuit but not when the computer is out of circuit. Wouldn't the relay prevent the car from starting? Isn't that what the electronics should do in a properly working car? Is there a transmission fluid level sensor and could that have caused my problem? Any help would be greatly appreciated.