With many old wooden double-hung windows, the bottom sash can be removed by first removing the wooden stop/molding along the left or right side, then the sash pulls out, held only in place then by the chain (or cord), attached to the weight (unless this is already broken).

HOWEVER, some old windows have a zinc/galvanized "track" attached to the sides of the window frame, along which track the lower sash glides up and down.
(via a groove in the side of the sash)..

HOW does one remove the window in this case ? (Without destroying the window and/or track).
The nails that hold the track seem to at all times be covered by the sash itself..

Has anyone come across this type of problem? I know that most old windows do not have these metal tracks on the sides...

Thanks,
Bennett

Show pictures.

Remove wooden stop on one side of window frame. You will see that the metal track only goes up behind sash a few inches. Starting at sill, use a small pry bar to remove track and nails. With sash in top most position you should be able to reach all nails. Then sash and track can come out together.

Good luck

Chuck