Hi I have a 99 infiniti g20; I left my lights on one day and I assumed it killed my battery. Later on that evening my mom tried to start the car (and it wouldnt start, battery dead)! She mistakenly left the keys in my car (with the keys to the on position). I tried a hot shot and it only cranked but didnt start, I got my battery charged and still the same thing. My dad determined it didnt have any spark from the plugs by putting his key inside and attaching it to a ground, it tried to start it again and he said it didnt have any spark! Heard it may be my ignition system. What do I do now? Troubleshooting advice?