Hi I can't turn on my mac book it's displaying question mark sign on screen
My Mac book is showing ? Mark blinking On screen
Troubleshooting portables that won't turn on or start up
http://support.apple.com/kb/TA25686?viewlocale=en_US
Troubleshooting: My computer won't turn on
http://support.apple.com/kb/TS1367
Look at A flashing question mark appears when you start your Mac
http://docs.info.apple.com/article.html?artnum=58042
Cheers, Tom 😉