This started this evening. I'm working on a project on my macbook, and all of a sudden the screen goes completely blank, and the cd drive starts making the sound that it makes when it ejects. This sound keeps on going on, like it's trying to eject something. (There's nothing in it). I have to turn it off and leave it for about 3 minutes, then when I turn it on it works again for about 30 or 40 mins then back to square one. Has this happened to anyone here?