Ibook

may be damge in connector cable (moost probable chnce as it moving throuth hinge

connect the laptop to an external monitor via it monitor out plug ,

I have the same thing happen to my iBook. If it's the older G3 version it's most likely the video card. This is a fairly common problem I found while researching on the net. The ibook's video card runs hot and the soldering between the mother board and the chip have become loose. Do you still hear the fan come on? Do the lights for the Caps Lock and Number Lock keys still come on when you press the buttons? When you connect to the VGA adaptor and try to hook up to a regular monitor does it still come up blank? Then yes it's the chip. Buying a replacement screen won't fix it. My fix was sort of a bootleg; basically take the bottom panel off, remove the silver heat shield and you'll see the chip covered in the thermal pad. Scrape the padding off, get yourself a good heat sink and cut the legs off. Make sure not to cut it flush or just by smaller mini heat sinks. Put thermal paste on the chip, put the new heat sink on, put the heat shield back in place, put the bottom back on. One thing to note is that the new heat sink you put on needs to be big enough so that the bottom cover and heat shield DON'T fit comfortably; needs to bubble out a little so that the chip is under tight pressure and presses firmly in place on the mother board. Like I said it's a bootleg but my ibook works fine.