After I turned down the brightness then I unplugged my mac book pro and took it anywhere moreover. I plugged it back the LED powers up at partially brightness. I am not able to adjust brightness to any further extent. The f1 and f2 keys do not run. The entire additional keys on my apple wireless keyboard run better. After going into Displays under System preferences. The merely alternative to adjust the brightness demonstrates as Color LCD, which is for my MBP. Under LED Cinema Display, There is no slider to regulate brightness. I have previously tried using dissimilar arrangements. Why cannot I do anything at present.