Just recently, my daughters ibook has appeared to go off for no reason. It happened to me today and I noticed that its still on, but the screen is dark. you can only just make out some images. I ve had the logic board replaced 3 times. Just wondered if anyone has any ideas before I start ringing apple tech tomorrow (oh no!) just plugged a crt into it and its ok. Backlight of the ibooks screen or could this be the logic board again?