If your PC has a backlit keyboard, press the F5 key on the keyboard to turn the light on or off. (It might be necessary to press the fn (function) key at...
Earlier, I used to refresh my laptop by just pressing F5, but now I have to press Fn + F5. Why is that? - Quora
![The F5, F6, F7, & F8 or ALT/F8 function keys do not work (FN lock) - eMarking AssistanteMarking Assistant The F5, F6, F7, & F8 or ALT/F8 function keys do not work (FN lock) - eMarking AssistanteMarking Assistant](http://emarkingassistant.com/wp/wp-content/uploads/2016/01/fnkeys.jpg?x54075)