Well, many power windows have a "resettable fuse" that shuts off when the current goes too high. It turns out that these electric motors draw more current when they are "stalled." So if someone sticks their arm in the way, the window will shut off or reverse. Some manufacturers use sensors and microprocessor control, however alot use the resettabel fuse things.
These are often polymer based fuses that can deteriorate with time. These fuses will be located at or very near the motor (they are not the traditional, replaceable fuses). If it's not the motor itself, it could be this.
Go to an online parts dealer and see if you they show a blow up of your power window. If they do, see what parts are available for it. But it sounds to me like you'll need to pull off the panel no matter what...