Hello I have the Originial MacBook 13inch and The Laptop Monitor Doesn't work. anyways it works fine on external Monitor, but every time i reboot i get this screen with lines on it and you cant see anything but lines and the only way to get it working again is to reboot it and plug it into my bros 23" monitor and than bring it back to my originial desktop monitor and then it works flawlessly and this doesn't happen when I put it in sleep mode or log off. Can someone Tell me whats wrong?