Most window regulators have cables, driving window glass. Either the cable is torn, the pully/gear driving it is broken (housing by the motor) or cable got loose and slips within "glass carrier" (whatever it's called) on the rail.
remove the window regulator from the door and inspect it, play with it.
Here's a picture for your viewing pleasure:
![Bicycle part Font Auto part Parallel Circle]()
remove the window regulator from the door and inspect it, play with it.
Here's a picture for your viewing pleasure:
