Paul,
What is the make and model of your laptop?
In a great many, but not all, systems this must be turned on or off in BIOS.? Lenovo, I believe, and at least one other major brand (not HP, as that's what I have and know it's a BIOS-based toggle) have utilities that let you toggle media keys/hot keys off within Windows itself.
Part of the problem is determining what the maker in question calls this feature, as it has different names, making it hard to web search for the turn-on/turn-off method if you don't know what your computer manufacturer calls the feature.
Brian Vogel