HP 421 Notebook-PC - Manual (Page 43)

Function Hotkey
Display system information. fn+esc
Open Help and Support. fn+f1
Decrease screen brightness. fn+f2
Increase screen brightness. fn+f3
Switch the screen image. fn+f4
Initiate Sleep. fn+f5
Initiate QuickLock. fn+f6
Mute speaker sound. fn+f7
Decrease speaker sound. fn+f8
Increase speaker sound. fn+f9
Play previous track. fn+f10
Play, pause, or resume a CD, DVD, or BD. fn+f11
Play next track. fn+f12
Using the keyboard 31