On November 19, 1995, about 1430 eastern standard time, a Cessna 210J, N3328S, inadvertently started while the pilot pulled the propeller through during the preflight inspection at Bellefontaine, Ohio. The airplane collided with a parked Beech C90; both airplanes sustained substantial damage. The one passenger (the sole airplane occupant) and the pilot (outside the airplane) reported no injuries. Visual meteorological conditions prevailed for the intended flight, no flight plan was filed. The local flight operated under 14 CFR Part 91, and was originating when the accident occurred. The pilot stated that he followed the airplane checklist when he attempted to start the engine. He reported: "Due to the lack of use of this [Cessna 210], the battery system was somewhat weak....the electrical system and battery did not have enough power to cycle the engine over." He stated that he tried to start the engine about 4 or 5 times by using the starter, then "...stopped trying to start the engine. I turned the master to the off position and turned the [magneto] key to the far left position. I proceeded to get out of the cabin...I slowly rotated the [propeller] over center one time, and the engine fired, to my surprise." The pilot reported that when the engine fired, the airplane began to move forward. The pilot instructed the passenger to shut the engine off, then tried unsuccessfully to open the pilot's side door to assist with the shutdown. The passenger reported that he tried to apply the brakes, then tried to pull the mixture and the throttle, without success. The airplane progressed across the ramp without anyone handling the controls. It collided with a hangar and a parked airplane, then came to a stop. Postaccident examination revealed that the ignition key was in the right magneto only position. Further examination of the magneto ground and ignition system revealed no evidence of malfunction/anomaly.