Help! no spark at coil

It is possible that the coil is defective. What fires the coil is the grounding and opening of the negative terminal. You can manually do that with power to the positive side momentarily ground the negative post with a jumper and you should see a spark from the coil wire (if it is placed close to something on the car) when you open the circuit . If you have missing or bad grounds from various components and or the engine to chassis this will also cause above mentioned problem. It could be in the ignition switch circuit or the ballast resistor also. Another thing to try is with the key in run jump the starter relay terminals (making sure the car is not in gear!) and see if spark appears. If it does then something is amiss in the starting circuit (switch or ballast) area.