A moped driver crashed on State Farm Road late yesterday morning and was transported to Watauga Medical Center for treatment of head injuries.  Boone Police said that 32-year old James William Nelson of Boone had just turned from the Highway 105 Extension onto State Farm, but witnesses said Nelson appeared to be distracted and found himself in the on-coming lane.  He tried to pull the small cycle back into the right-hand lane, but lost control and slammed head-first into the pavement.  Witnesses and Boone Police said that Nelson suffered a gash to his head and face, abrasions, and possible should injuries, with Watauga Medics transporting the Boone man to the hospital at the other end of State Farm Road.