I have Better Bilt windows and screens (series 3740 single hung aluminum windows) which were purchased from Lowes in 2005. The push spring screws which hold the screens in place (and which can be removed in order to clean the glass on the windows) are broken and crumbling (probably due to our heat in Fl.) Lowes has indicated these windows are no longer made and they don't have replacement parts for them. Can you help?