Switch Fn key state

On Lenovo Thinkpad Edge, press Fn+Esc and Fn key will light up and you can use F1-F12 keys as default.

Press Fn + Num Lock to disable it.

It's a bios option. Look for 'enable media keys' or 'enable function keys'. Often it's worded differently, dig around. Honest, it's there.

It's nothing to do with your OS, as this would be happening regardless of what you're running. The bios toggles a bit-switch somewhere and the keyboard firmware uses that to determine if a Fn-F1 is F1 or something else.

Unfortunately, the vendors have decided we need to be playing music more than we need to be using F-keys as selectors. Logitech keyboards do this too, and there's a way to flip their 'default state' as well.