No fire to engine

I have a BMW 325i 1993 that is cranking but not firing. The car has cranked fine until now. The car sat for 4 days without being ran and when I got back in to crank it, the car turns over but does not fire. What would be the most likely problems and how would I test them to find out what the problem is? I have a repair manual but it's not helping out on what the problem may be. I am desperate for help. Thanks in advance for any help you can give me.

Pull the coil wire from distributor and ground while cranking, if spark, likely problem is bad cap, rotor, wires
If no spark,
test voltage to coil positive terminal (should have battery voltage with ignition on),
if voltage is correct, most likely or pickup coil air gap (in distributor), bad ground at control module (ICM), or bad coil.
If no voltage or incorrect (assuming battery is fully charged) likely ballist resistor, or wiring from ignition switch to coil.

Could also be crank sensor if no spark