After many days of research, I found that the last Catalyst Control Center and even the driver alone is turning off the light of my laptop screen (Asus X72D) but not the HDMI display. I assure u that my screen isnt damaged and can work as usual when I install a clean Windows 7. I try everything possible in the settings of Windows and in the Catalyst Control Center.
I had the same problem a year ago on another computer but cant remember how I fixed it.
Merci beaucoup pour toute aide apportée à mon problème !