It is easier to remove the upper sash by working on the window from the outdoors, if this is possible.

To free an upper sash from the outside, pry away the outer molding strips.

These divide the sides of the frame into two tracks, one each for the lower and upper sashes.

However, if you cannot work from outside, free the upper sash by removing the center strips of molding instead.

The glass was absent from the upper sash.

The upper sash is the one that fits in the outermost window tracks.

They have small panes in the upper sash with a single pane below.

To replace cords attached to the upper sash, you must remove it also.

The upper sash can then be lowered and tilted out of the frame.

To free the upper sash, you'll have to remove the parting strip between the two sashes.