How do i activate the num lock and scroll lock in dell n4050?

Recently,I had win 7 ultimate 32 bit and i was able to turn the num lock and scroll lock  on the keyboard of dell n4050.I think they are on the buttons "J" and "F".But my windows got corrupt.Now i renstalled the windows but the lights on J and F buttons dont illuminate when i press the Fn key and "J or F" and also i cant turn on or off num lock or scroll lock