Ok, for some reason, when I play Minecraft at home (on my laptop, I don't own a PC), my F keys don't do what their supposed to do (e.g., pressing F5 doesn't put you into third person mode, pressing F1 doesn't remove your HUD). Any help?

You may have your 'Fn' or function key locked on. Since a laptop has a limited number of keys, they make a lot of them do two things (like a scientific calculator)

Try holding the 'Fn' key and pressing scroll lock (which might be abbreviated to something like 'Scr Lok')

Um, I don't see a scroll lock key.