My 2006 f150 wont start

if your car is starting a few times and you are running it the only thing that charges your battery is the alternator. The stereo guy, is a long shot is creating a situation where you battery does not start. There should be a main power wire that was hooked up to your battery and there should be a fuse right by the battery to dissconnect the power. you d not have enough information to actual diagnose this through email but here is what i would try. Dissconnect the power wire that he installed to the amplifier.. if he has the trigger wire directly connected to the power wire the amplifier will stay on and can drain the battery. In your question its hard to know if you have a dead battery and are recharging it or it cranks and will not start. I am assuming that you have a dead battery. So the stereo guy culd have wired it to stay on all the time.. you can check this by shutting off your car with the key out and look at the power light on the amplifier.. if its on with the key out then it is constantly on. There is a second wire that needs to be wired to your ignition switch, the trigger wire for the amp, which will only turn the amplifier on when you turn on the ignition. If it shuts off then i would check to see if the alternator is charging the battery since you can start it a few times and then it goes dead.. once again its hard to tell unless we knew if the battery was going dead on you or if the car cranked and didn't start. If the car is cranking and it just does not start you do not have a power issue. Let me know when the battery is going dead and i can help walk you through a little trouble shooting on it.