For those who had problems about reversing the fn key function, and do not have the numlk key.. what I did was go to the setup utility(BIOS) and go to configuration settings.. and disabled action key...
This problem occurs to those who have notebook laptops like mine.
To enter BIOS.. just turn on your pc and enter the appropriate key to enter setup.. usually it is esc delete f2 or f12.. then just follow the steps above.
after doing these you can test it by pressing the fn+function keys to know if you had it reversed...
HOPE this helps and sorry for the wrong grammar.