45-year-old storm aluminum self-storing storm window
Thank you for reaching out to us. I'm afraid we don't sell replacement windows or frames. Are you looking for the corner hardware? If so, we will need to see photos of them removed from the frame along with the written-out dimensions.
Same problem with the insert. That is a different window and that one is 21 inches wide. I have already duck-taped that one, so I'm attaching a picture of one that has NOT fallen apart, so you can see how the corner looked before. No corner hardware.
I actually see a corner key in your first photo here but I'm not able to identify it when installed. Seeing it removed from the window along with the written dimensions of the corner itself is the only way I can help. However, you're more than welcome to browse our selection here.
If you aren't looking for the window hardware then we can't help, unfortunately. We can only assist with identifying unknown parts. I am sorry for any inconvenience.