HP laptop F1-12 keys inverted with Fn
I can use Shift+Fn (actually Fn + Shift, button-down-order seems to matter here) on my Elitebook to invert/swap Fn and F-Keys (aka "lock Fn"). The keyboard indicates the current mode with a little light on the Fn key and also shows the switching option printed on the Shift-Key, see screenshots attached. Sometimes it's worth checking the printings on the keyboards before using google thought - learned it the hard way ^^
Apparently this can be adjusted in your notebook's BIOS.
From HP's "Disable The Fn + Function Key Combination on Certain Models":
On most HP and Compaq notebook PCs, it is necessary to press and hold the function key (fn) while pressing one of the f1 through f12 keys to activate the default functions; such as, increasing or decreasing the brightness of the display, the sound volume, sleep, keyboard lock, etc. On the HP Envy notebooks and other notebooks with advanced BIOS options, the function keys can be configured so that it is not necessary to press and hold the fn key.
Complete info (with pictures) is available from HP (see link).
Usually, you can boot into BIOS at startup with F10, and look for the system configuration option. Look for "action keys mode," or something similar, and toggle as desired.
More detailed instructions if needed:
http://h10025.www1.hp.com/ewfrf/wc/document?cc=us&lc=en&docname=c02035108