start yr netbook, when it show Dell loading screen, press F12 (boot options).
pick the bottom option (enter setup)
n then choose the second tab from the left with yr keyboard (Advanced).
pick the option "function behavior" press enter
the choices are multimedia and function.
from what i read, yr fn behavior must be at multimedia. so pick the other one. and choose exit tab, save changes and exit.
n you dont hv to repeat this step everytime you start yr netbook, coz its fixed..
hope it'll help.