Only my drivers side front window is working right now. With the other three they do nothing. On one of them you can hear the motor trying to work but it doenst roll down. Did that one maybe come detached somehow? The others make no noise when you try to roll them down. Should I replace the motors and regulators on all three? Is that difficult? Also when I took off the panel to look at one of the window motors there was some plastic covering all the openings under the panel, is that ok to pull off? Any help would be great! Thanks