start your netbook, when it shows Dell loading screen, press F12 (boot options). pick the bottom option (enter setup)
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, your fn behavior must be at multimedia. so pick the other one. and choose exit tab, save changes and exit.
You don't have to repeat this step everytime you start your netbook, because its fixed..
Hope it'll help.