98 sunfire wont start

[frustrated_sunfire]

I have a 98` pontiac sunfire that will not start. It will turn over fine just wont crank. The alternator went out, killed the battery. i replaced the alternator and battery, then found out the wire that connects to the alternator was broke. I fixed that and the car started fine, i drove home and as soon as i killed the car it would not restart. I tested the alternator its fine the battery is fine. i replaced the crankshaft postioning sensor and its fine. I checked the spark plugs and none of the cylinders are firing. i have had this problem before and it was the coil packs. I have replaced the coil packs at least 10 times and the coil housing twice. the coil housing tested fine. I took the ignition module off and had it tested , it was fine. the guy at the auto parts store told me that the wire being broke off the alternator and then driving it fried my ecm. if thats the case why did it still start and run 3 more times? any help would be appreciated thanks