On March 14, 2003, at approximately 0730 mountain standard time, a Piper PA-24-250, N6960P, operated by the pilot, was substantially damaged when it impacted terrain during a forced landing near Alexander Municipal Airport (E80), Belen, New Mexico. The pilot was not injured, but his passenger sustained serious injuries. Visual meteorological conditions prevailed. No flight plan had been filed for this personal cross-country flight being conducted under Title 14 CFR Part 91. The flight originated from Tucson, Arizona, at approximately 0530. According to the pilot, he purchased the airplane on March 11, 2003, and was aware of recent maintenance on the fuel selector valve. He examined the airplane and departed on a cross-country flight back to his home base. He stated that, approximately 2 hours into the flight, the engine "quit," and that he had experienced fuel exhaustion. He switched the fuel selector valve to the left wing-tip fuel tank, restarted the engine and landed at the nearest airport. Upon landing, he examined the fuel tanks and found that the right main and right wing-tip fuel tanks were full, the left wing-tip fuel tank was half full and the left main fuel tank was "dry." He refueled the airplane and departed. During the next 2 hours of flying, he switched the fuel selector valve from the left and right wing-tip tanks, to the main tanks and at approximately 2 hours into the flight the engine "quit" a second time. He was able to restart the engine after switching back to the left wing-tip tank, landed at the nearest airport to refuel and then departed to his destination. On March 13, he flew the airplane from his home base to a nearby airport with a maintenance facility to have a mechanic examine the airplane's fuel selector valve. The mechanic stated that the right fuel selector valve did not have a detent. The pilot had the selector valve repaired. The selector valve was checked and it operated correctly. He then departed back to his home base. On March 14, the day of the accident, he departed on a cross-country flight. During the second hour of flight, he switched the fuel selector valve from the main tanks to the left wing-tip tank, then to the right wing-tip tank and then back to the main tanks in 20-min intervals. Approximately 2 hours into the flight, the engine "sputtered and then stopped." He restarted the engine, but it only ran for a few seconds. He attempted to glide to the nearby Alexander Municipal Airport, but was forced to land approximately 250 feet short of runway 21. The impact resulted in a cord wise buckle of both the left and right wings approximately 4 feet inboard of the wing tip tanks, the displacement of the engine, the separation of the left side of the firewall from the fuselage, and the separation of the left and right main landing gear and nose landing gear assemblies. According to an FAA Inspector, there was approximately 60 gallons of fuel remaining on-board the airplane. The fuel was located within the left wing tank and the left and right wing-tip tanks. The right wing tank was empty.