Now it works like that:
it was running OK until I moved a file from the desktop to the HD...
Reboot: black screen...
Reboot again: same.
Re.. : the apple coming up, good, and the weel, OK, and freeze!
Re.. : finally start up all the way, but flikker skreen is coming now..
hummmm.... open and close the Book, and see some changes, only frozen screen... then put some pressure on the top right edge of the screen (making an effort on the "U" that links the "screen" to the "computer" part) and it turned into my good old color bloks... press on the other side, back to the fliker,...
Then i try to "stabilize the image of my frozen apple and wheel... and reboot.
As u can read, it worked...
Could it be THERE? this "U" that links the 2 parts could be deffected and foks up the all stuff??
I manage to rename my HD in a "black screen" reboot, but I still dont guet it! It doesnt boot at all so many times that a video problem doesnt look "enough" to me..
Any help? A processor problem? I m kinda lost there!...