Engines running need 3 things. Air, fuel and spark. To some extent the fuel needs to be the right quantity (a little too much - like the suggestion of spraying starter fluid) is OK to run. As for spark, it needs to come at the right time (hence crank and cam position sensors).
Air is pretty simple and almost never lacking. Fuel, make sure the computer is work (scan tool reports no problems) and you have pressure on the rails. Most/Many fuel systems have a shrader valve to test fuel pressure. Fitting like a tire air fill - poke it with a small screw driver and gasoline should squirt out.
As for spark. Assuming the computer is good, there are various tools that can detect spark.
One last thing. If the car fires up for a few second, then dies. Consider the possibility of a clogged catalytic converter. A missfire (your earlier problem) could have sent raw fuel to the converter which processed it (burned it) and overheated - internally melting, forming a clog. Since you fixed the spark issue (hopefully), just replace the converter.
If the car fires for 1 second and dies (instantly). Look for a sensor malfunction. Cars with MAF sensors. Essentially the computer detects no air-flow and puts in the appropriate amount of fuel (which is zero -for zero air). Some cars you can unplug the sensor and the computer will estimate the amount of fuel needed - it just wont run as smooth or efficient and throw a check-engine light error.