Ask Max: Mac with Grey screen color and blinking question mark
How do I fix the Grey screen with the blinking question mark?
The flashing question mark of horror… it is not always a day-ending event, it really just means your Apple Mac has tested all the equipment and is ready for the next step. The ™horror™ comes from the next step being ™start loading the OS from this disk,™ which is not happening. It could be that your hard drive has died or the OS is corrupted but it can be as simple as the computer forgot what drive the OS is on.
Try restarting the Mac computer by holding down the [option] key, which will take you to a boot loader. After a few minutes all available boot devices will show up. If your Apple computers hard drive is not listed, then you should put in an OS X install or Restore DVD. See if you can see the internal drive from the Disk Utility included on that Install disc, when booted from it. There are some diagnostic tools under the ™First Aid™ tab in Disk Utilities that may help.
If you are lucky, and can see your drive from the boot loader, then you should select your drive and boot up off of it. After you boot up, use the Startup Disk section of System Preferences to permanently select your hard drive as the boot drive.
If your drive is there but has damage to it, Disk Warrior is the best home drive repair tool for Apple computers.