i have a bmw...and it was working great today then suddendly i parked in a parking lot and came out....and the car would turn on but not start up.....what possibilities could it be??? my dad was saying it could be the starter.....im going to get it towed tommorow ...but any idea what it is and how much it would cost to fix....

its so wierd b/c it was riding like a dream and then....