Lock/unlock function keys on Apple keyboard

I made a post about this recently, although I hadn't arrived at the point I am now, where I'm able to express the issue more clearly and hence I'm making this new post in case my last reply on the other one doesn't receive as much attention as a new post might.

The problem is that the only way to register a button press for the F1-F12 keys is to press Fn + F1 in order to register an F1 press, for example. If I could lock (or unlock: not sure which) the Fn key, this ought to solve the problem, but I've as yet been unable to do so, since I see no 'Fn lock' key (or icon above any key), haven't found a key combination (such as Fn + Caps Lock) which does it and haven't found a way to lock or unlock it or the F keys in any of the pc settings. I do plan to search for (function keys) or something in control panel and/or settings if I get on the pc again.

Any one and idea if this is possible and if so, how, please?