Asus G73SW PLEASE Help =(?

I recently got this laptop, and i LOVE it.. BUT when i hold the Fn+f3/f4/f9/f10/f11/f12 keys... THey dont seem to work, every other key does, like if i press Fn + f5 the screen dulls a little, and fn + f6 brightens it, but i can't seem to figure out why the keyboard light wont turn on anymore >.<