i buyed today a new hdd, because old is dead. and to pull it inside, i had to open all mac book, because the rubber from side was in the back. but it's not the main thing. when i turn on computer with new hdd. it only black screen. actually it's off. and he just flashes for milisecond in the begining and thats all. and cd of mac os it's inside. and can any one help me?