Currently all green lights, ready to fly... just motors "twitch" and wont spin nor takeoff. Background: removed the prop guards and the plastic mounting brackets, then mounted the motors with the same LONG screws... (believe the long screws interfered with magnetic field of motors, and now does not fly). Motors were never stuck (zero movement), but just hand spun - slower and stickier. Since then, I reassembled with prop guard mounds, but she doesnt fly... all green lights, ready for takeoff... just one motor twitches, and none of them spin. What might I have burned out?