Responder a:Can't boot up - stuck at spinning wheel against grey backgroundhi, im having problem too with my mac air. it suddenly went hanging , my cursor just stucked and i cant do anything to it even aftr pressing any keys. so i tried restarting it but then it got stucked on apple logo screen, then i tried to press the option+command+p+r keys but the screen keep on turning on and off with the chimes sound. what should i do? pls help .