Window Replacement - looking for source or advice

How doe the frame seal to the window glass - is it glued to the frame or is there a rubber gasket of some sort? Can the frame be disassembled without special tools, and without damage to any plastic pieces that are present? I would try to seal it myself if I knew that I had a source to buy a replacement quickly if it went bad. Don't like the idea of having it in storage with plastic sheeting covering a big opening - too inviting to thieves...