The slider can be replaced by removing the inner retainer ring, slide out the felt channel and wedge the frame a little wider. The fixed pane will require removing the whole window and removing the screws where the frame is spliced together. Use a putty knife between the window frame and the fiberglass to unstick the rubber gasket. When reinstalling the window assembly, I suggest you put a light bead of urethane sealant on the rubber gasket, to insure a water tight seal. I spent some money with Sue, earlier this year.