Depend of the problem. Usually you replace the screen. And if you have a recent "anti-repair" macbook (these without screw) I really recommand you to send it to a certified Apple repair center. To remove the screen, you need to: 1 - Take the whole thing apart. It's not a PC... You will not find a simple to unplug connector under the keyboard and so you might even need to remove the mother board. 2 - Once you can remove the LCD assembly, remove it and put it on a heat-resistant desk, protective glass on top. 3 - Take a heatgun, heat it to 350C and heat that protective glass all around. (the section around the LCD need to be heated, not the LCD himself) 4 - if hot enought, place the suction cup on a corner and pull hard. If it's not hot enought, the glass will shater. 5 - once the protective glass is removed, you can follow standart PC fixing method (unclip, unscrew, remove lcd, disconnect, put new lcd, reconnect, place it correctly, screw, clip) 6 - put the protective glass back (you may need some glue or adesive tape.) 7 - Build you Apple back, reconnect everything.