Black screen with question mark

Please review all the steps in If your Mac doesn't start up all the way - Apple Support and follow to the letter. The final step of each is to take the computer in for servicing if everything fails. As long as you have a good backup of your computer there isn't anything to really worry about. If you don't know where to take the computer for servicing please click Apple Authorized Service Provider Locator (AASP) & Genius Appointment. NEVER EVER take a Mac to the local computer repair shop. ONLY take it to an Apple Authorized Service Provider!!!