Chester, West Virginia:Former WBO heavyweight champion Tommy Morrison stopped John Castle in the second round on Thursday in his return to the ring 11 years after testing positive for the virus that causes AIDS. The 38-year-old Morrison, who claims he has no trace of the AIDS virus after taking several HIV tests, dropped Castle with a left hook to the head midway through the second of the scheduled four-round fight at Mountaineer Racetrack and Gaming Resort, about 100 kilometers northwest of Pittsburgh. Castle slowly got up and referee Dave Johnson counted to eight before stopping the match. Morrison (47-1-3), who until that point had landed few punches, fell to his knees afterward and raised his arms skyward. "I wanted to show not just the fans but myself that I'm not lying to myself," Morrison said. "For the first fight in 11 years, with a win under my belt, I'm pretty happy." Medically fit Castle hadn't fought in nearly two years but said he wasn't going to fight Morrison until he personally reviewed Morrison's medical records. He got the chance to do so about four hours before the fight. Morrison won the WBO title in 1993 by outpointing George Foreman. He lost it later that year. Morrison, who was featured in the movie "Rocky V," also served a couple of years in an Arkansas prison on drug and weapons charges. In February 1996, Morrison tested HIV positive just before a scheduled fight against Stormy Weathers. At the time, Morrison said he likely contracted the disease through a promiscuous sex life. Morrison said earlier this week he has taken several HIV tests while preparing for his comeback and all have been negative. West Virginia Athletic Commissioner Steve Allred approved Morrison's participation after reviewing medical records and consulting with the Association of Boxing Commissions' medical review committee.