when looking at the hard drive where the power plugs in .... there is a flat horizontal bar and towards the other end of it curves to a vertical part .... the curved part and vertical part is missing
Something must have hit it and chipped that piece of the plastic off. There's nothing you can do about it and if it isn't causing a problem, don't worry about it. It's like a door ding in your new car. You don't like it but you move on. Sure, you could replace the hard drive but it wouldn't be worth it.