If one failed, and then another some time later, they may be just sticking in their tracks. Open the door, look at the panel at the bottom inside of the door, it may be a storage tray or vinyl trim.
Get somone to operate the window switch and while they are pressing it, wack the panel with your open hand, hard. this may free up the sticky mechanism. Car rental companies do this all the time.

Check the fuses if ok check the wires as they go through the door frame may be broken wires.