My home was built in 1984 and is a former model. It has black aluminum framed sliding windows. Several of the windows' rollers have developed "flat spots" making them "bumpy" upon opening and closing. Can't find replacement rollers (on web or from local window repair companies). No manufacturing info is apparent on the windows and frames. Is there a company that stocks hardware for hard to find windows parts? Also, prior owners' kids bent several of the screens at the bottom. Need to know if there is a way I can straighten them out and replace the screening or if this is a job for a professional.