We're trying to remove the four original fixed windows from our 1976 Irwin 37. They have riveted aluminum frames inside which I assumed once removed would allow the windows to be forced inward for removal. But now that I have one of the frames removed it isn't obvious which way they should come out. Has anyone encountered this problem before? Any advice on the best way to remove them? I'm planning to use the old windows as templates for the new plexiglass ones we will replace them with so removing them in one piece would be preferred. Thanks! -Steve