sounds like the wiring to me, have u tried opening the door and pulling back the rubber sleeve to look at the wires, when i had a look at mine the broken wire was obvious. AFAIK the regulator is the window mechanism itself probems with these seem to be when the cable which pulls the window up and down gets frayed and sticks, or the plasic connection on the lifter that fits onto the cable bead breaks fuses would be in the fuse box i imagine, just below the steering wheel???