The same this has happened to my passanger side rear window. The back ones are cable driven and the plastic piece at the top that the cable slide throught broke not allowing the cable to go high enough. You can try taking the door panel off and push the window up. Since mine was a back window. I just got it up as far as I could and took the fuse out so nobody could roll it down. I've seen the new regulators on e-bay for 54.95 if you wanted to go that way. Or you can let a local shop look at it and give you an estimate.