For the needle threader, its the worlds tiniest crochet hook and if it gets bent it needs to be replaced typically, you can sometimes bend the hook back but it doesn't usually hold very long. I would make sure you aren't using a needle smaller than 80/12 since, since any eye smaller will most likely bend the hook on the threader. For the accufeed system, it is highlighted in yellow when it's activated and blue when its off. it should be activated anytime you are using an accufeed foot, and deactivated whenever you are not using an acufeed foot. I can note that having it activated while not using an accufeed foot will not cause any adverse affects in your sewing. There will simply be an extra part moving in the machine that doesn't need to be moving. Hope that helps!