Thanks WisM - I did get in there and everything appeared tight and on track. So I replaced the regulator and put new plastic clips in for the rail (the old ones did have a broken corner each). Everything back together and working... except... same problem. The new adjustment screw came with a plastic tip that seemed to catch the edge of the stop... for the first try or 2. Then it "popped" and the window went right on up too high again! (grrrrr...) So I took a trip to the hardware store and found an oversized metal "head" thing that I could screw onto the adjustment screw to make SURE it caught the edge. Same thing... worked for a try or 2, then "pop" and the window went up too far. That's when I figured out that the door panel is actually flexing under the pressure of the window motor! So the stop just gets pushed out of the way!!! I'm now thinking about trying to bolt a plate onto the stop to extend it out under the adjustment screw, but who knows if this'll create new problems. Again, any help would be GREATLY appreciatted!