It turned out that professionals were useful.
All hail Home Hero, who told me that they didn't do that sort of work, but Oregon Window Co does. (Oregon Ave. is a street a couple of miles from here.)
Semi-all hail Oregon Window Co, who fixed two screens properly, but neglected to replace a pin in the third screen. Fortunately, the third screen isn't urgently needed.
This entry was posted at http://nancylebov.dreamwidth.org/1049570.html. Comments are welcome here or there. comments so far on that entry.