Why doesn't the dual switch on the driver's side work for the electric windows?

I would guess a switch. To make sure, you will need to take the door panel off and get to the window motor connector. Get a test light, and connect it to the 2 wires going to the motor. If the light turns on when you work the switch, the switch is probably good. You can check the window motor by giving it power and ground, if the motor works, and the switch turns the light on, then you have a wiring issue that can be difficult to locate. I would recommend taking it to a professional at that point.