Awning windows, I suspect. Are you in a hi-moisture/rainfall area/high humidity?
The weather strip may be binding or the wood has expanded because it has taken on moisture which would make the weather stripping bind even more.
Is the wood actually rotting or is it just swollen from moisture?
If you can remove the whole awning piece and let it dry, you can then seal it with a clear coat to prevent moisture intrusion and have an operable window until you can replace them.
There is even an epoxy fill product that you can use to restore/rebuild the same window. If you want a link, let me know.
An alternative to new windows are insert windows
. With inserts, you don't remove the outside trim, the old window jambs or the inside trim. An insert window can be installed by any handy person in less than an half a hour.
They can be "glued" in place with low expansion foam that will make them much more energy efficient than your old windows.
The outside can have a prefinished metal or plastic trim on it so there's no outside painting/finishing to do.
If you're interested, I'll have a salesman drop by next week ... just kidding. I can provide some links to some really nice insert windows. Every major US window manufacturer, Anderson, Pella, Marvin, makes them.
Don't get buffaloed by the "replacement windows/siding" hype. They are usually high priced, often but not always with inferior quality windows.