Screen black often doesn't boot, if does boot, screen flickers?
rev A 2008 MacBook Air most often doesn't boot, screen stays black, (looks like the backlight it is on though).
Sometimes after a variable delay it gets to grey screen and Apple logo and it starts to boot up, even before it gets there a horizontal multicolored striation flicker most often appears on the screen and it then usually goes black.
Sometimes but not often enough(!) it will boot and the machine appears to perform as normal and is usable, but at any time the flicker to black may reappear.
Have wondered if its a sympton of the SSD beginning to fail?
This machine has had a hammering in terms of continuous trouble free (apart from getting hot) use since it was bought in 2008.