Display backlight off ?

[Polli]

This DELL XPS 15 L502x laptop has:
GPU #0: Intel HD Graphics 3000
GPU #1: NVIDIA GeForce GT 540M

Haiku boots correctly from the USB stick, with very few exceptions (nothing found there to boot: Operation System not found). A big problem is that sometimes, even after booting 10-15 times in a row, I can only dimly see that Haiku has booted successfully (backlight not on?). I tried to recognize something: it seems almost as if the contents of 2 open folders are somehow scrolling or similar to display order/sorting constantly change It used to show (1 year ago, among other things).
IMAGE DISPLAY: AU Optronics 15.5"
Now: DO NOT USE AUO 15.5"