COBALT LOST ALL POWER. WHILE REACHING FOR KEYS TO TRY AND RESTART COBALT, KEYS WERE NOT IN IGNITION SWITCH AND MUST HAVE FALLEN OUT. WITH NO POWER TO STEERING I KEPT MY LEFT HAND ON STEERING WHEEL AND REACHED TO THE FLOOR WITH RIGHT HAND TO TRY AND FIND KEYS. AT THIS POINT IN THE BLINK OF AN EYE THE CAR STEERING WAS UN RESPONSIVE AND COBALT VEERED OFF THE ROAD TO THE RIGHT DOWN THROUGH A HALF PIPE SHAPED DRAINAGE DITCH AND DID A ROLLER COASTER DOWN THEN UP IN THE AIR AND THEN SLAMMED BACK DOWN TO GROUND COMING TO A STOP. IN THIS ROLLER COASTER EVENT I WAS TOSSED INTO THE INSIDE ROOF OF THE COBALT THEN WITH SEAT BELT ON PULLED/SLAMMED BACK DOWN INTO SEAT ON MY LOWER SPINE THEN THE SEAT BROKE LOOSE FROM ITS POSITION AND SLID FORWARD SLAMMING MY LEFT KNEE INTO THE LOWER DASHBOARD AND BROKE THE DOOR WHERE THE TRUNK RELEASE IS LOCATED. POLICE WERE CALLED, REPORT TAKEN I WAS DISPATCHED TO HOSPITAL VIA AMBULANCE. *TR