Q: honda civic lx wont start

Saturday, Feb 4th my 2001 Honda Civic LX maint. required light came on (it does not have a check engine light). I took it to autozone where they plugged it up and gave me 3 papers each with a code for the problem and each problem had 3 to 4 probable causes. On my way home the car cut off twice. The next day (Sunday Feb 5th) i put a new catalytic converter on the vehicle because it was on the paper and said to be the most likely cause. It ran better but started over heating and paper white smoke started coming from the exhaust pipe. 3 weeks prior the radiator busted so i put a new radiator and thermostat in the car. That having been done already, after installing the catalytic converter i put in a new water pump (again the cat converter and water pump were installed sunday feb 5) when i finished with the water pump i tried to start the car. It will turn over but not start. When i turn the key back from trying to start it i hear a short soft puff of air from under the hood.
My car has an automatic transmission.