It probably hasn't fallen off the track. The part of the window regulator that attaches to the window is probably broken. Mine did the same thing. I took the window and regulator out of the car and epoxied the part back together and then reinstalled it. Been over a year now and still working fine.
To repair a stuck driver-side manual window, use a screwdriver to remove the screws attached to the door panel. Pull the door handle away from the door and lower the window regulator to the lowest possible position.
Go to the junk yard and and buy the window with the plastic guide attached to it for about $70. Otherwise, it will cost you about $430 at the dealership and about $175 at some glass vednor plus another $100 for installation.