IBM ThinkPad A31 Notebook "crescent key keyboard" Questions

crescent moon lit, but i dont know why its not turning on, its plugged and everything. Press and hold the blue Fn key while pressig the F4 wait a moment and see if it wakes up This is a common problem

...on my HP laptop is located. It's a Fn key combination on the keyboard. Press and hold the Fn key down and then press the key with the crescent moon icon it. This is the equivalent of the sleep

...key on your keyboard has a crescent moon type symbol...if you use it with function key..your lappy will hibernate...some other keys may be for brigthness of your screen ,increasing and decreasing ...