EDIT: Updated information at the bottom!!!!! \/ !!!!! Hi, right a few days ago i plugged in a HDD from another mac into my mac via an external HDD to recover some of the stuff off of there for a friend and after about 1-2minutes it had froze my mac and wouldn't do anything so i turned it off by the on/off button because that was the only way and now it won't boot, it stays at the apple logo screen with the little spinning sign going round and around. I also haven't got a back-up of my work so i really my stuff because theres about 200GB worth of data on there. If anyone could help me out into telling me how to get my mac to boot i would be really greatful. Thanks, Greg.