I had the same problem. Open the driver's door and shake it back and forth in the open position. If you hear something moving around then the lower window track has come loose and is now in the way. I've heard it needs to be re-attached or welded.....but I took apart the door panel and removed a plastic insulation cover (right behind the door pocket on the door panel. I then pulled out the lower rail that fell loose. Works fine now, even without the lower rail. Haven't had any problems since then. Who needs the lower window rail!!! Seriously though, I hope I'm not screwing anything up without that rail.....good luck....