オリジナル投稿者： Jason Heiken ,
Make sure you'r MacBook is completely powered off. Press the power button, and then press and hold the ALT key. After a few seconds, you should see a selection of icons that will let you select a boot device. If your hard drive is there, select that. Or, if you see one labeled 'Recovery' select that. If you select your hard drive and it boots, go to Disk Utility and run verify your disk. Then go to System Preferences and verify your drive is selected as the start up disk. If you select Recovery, choose Utilities from the menu bar and open Disk Utility. Verify and Repair your disk. Once that's done, try booting again. If those steps don't work, please provide a few more details, (like what OS you're running) and we'll move on from there.