Having to use Fn key to order to use F1-12 buttons on Pro 3 keyboard

[BGrewer]

A couple of minutes ago I tried to alter the screen brightness and access the settings, via the buttons on the surface pro 3 keyboard, and it wouldn't allow me, it kept directing me to help pages (F1) and reloading the page (F5) I don't know how I have done this, but if anyone knows how to 'reset' of fix the keyboard could you please let me know-as I don't know how I have done this and don't know how to rectify this so now I have to press the Fn key in order to use the F1-12 buttons (backlit keyboard brightness, mute, play/pause and the ones on the charm bar)

 

[theefman]

Press Fn + Caps to reset the function lock.

 

[BGrewer]

Thanks theefman!!!