Yes, remove the door panel. You didn't say what car it was, by the way? 300SD I did required removing 2 screw at botton of door panel, chrome molding on door edge, screw lock button, door pull, and maybe door handle (don't remember for sure).
Probably you will need new regulator. Sounds like teeth may be gone or regulator is broken. If you still need to drive car while getting replacement regulator I just stuck a piece of wood cut to length to hold up window: hillbilly engineering. Window motor was held in place by a couple of screws with allen wrench heads (I'm mechanically challenged). Never had to actually remove the motor just detach it from the regulator. Lot of little odd pieces to keep track of. Just go slow. I had to do this with three windows. Would not want to do it again but I'd be much faster next time.