Alright my macbook was working fine last week. I hadn't used it since Friday. Today I turn it on and it goes to the gray screen and stays for like 15 seconds or show then shuts down. I insert my OS disk to start from there and do repair disks and it won't allow me to do that saying errors with repairs. Is my hard drive screwed? Anyway I can save anything on my hard drive or must I just reformat it all over again??? Thanks.