Vostro 3450 - Driver(s) to control function keys

Hi all.

I had to format my laptop Vostro 3450 but I cannot get which drivers I have to install to visualize screen icons when a funcion key is pressed.

The keys are working, so if I press Fn+F2 i can switch on-off my wireless connection but before formatting a spash icon was appearing on the screen and now is not.

Not a big deal but annoying as you don't get on the spot if your action was performed or not.

Any help/suggestion?

Thanks