so i have done thing's asked me one by one....
the first was :
    Reboot with only the kernel parameter acpi_backlight=vendor :

        Make a comment on if you can now alter the backlight with hotkeys or a brightness applet.


then, i have a intel_backlight folder, so i did this:

If you have the folder /sys/class/backlight/intel_backlight/ :

    type sudo su , and then execute:

    ls -la /sys/class/backlight/intel_backlight/ > lslabacklight

    echo 8 > /sys/class/backlight/intel_backlight/brightness
        Please comment on if the brightness changes. 


and my brightness has come down. but how do i fix the hotkeys problem? how do i get is high again??