I turned A/C on first time this year and the belt squealed really loud, then I tried to turn the engine off and the truck wouldn't turn off. Just idled rough for roughly 2 min until it shut off. Cranked up and ran fine for a week. Tried A/C again and it was nice and cold. Pulled in to get gas and truck shut off fine. When I cranked the truck it squealed really loud, and couldn't shut the engine off, sounded like the starter was continually trying to start the vehicle. Finally I turned the key back on and pressed the throttle and the squealing stopped, it cranked back up and drove home. Hasn't happened again and haven't tried the A/C since. Any help?