I just got an iMac and the F10, F11, and F12 keys which I thought were volume keys are not adjusting the volume. Instead, when I press the F11 key it gives me the desktop and the F12 shows me the widgets for the calculator, weather and all that stuff. How do I get those keys to adjust my volume? Thanks.
What he is looking for is actually under: System preferences > Keyboard & Mouse > Keyboard Uncheck "Use All F Keys as standard function keys"
It's System Prefs, over to Keyboard and Mouse, under the Keyboard tab there is a checkbox for "Use F1... etc as function keys", you want that unchecked in order for the F1 keys to function as the secondary icon on them (i.e., dashboard, volume, expose).