Problem with hotkeys in Tibia

As the title says. I just bought a laptop with Windows 7 installed. Today I logged in Tibia and I tried to use any of hotkeys to cast a spell, but instead of activating spells in a game, the only thing, that I actually activate is things like Help, Brightness balance, some software installed on computer and many things, that I don't want open. The thing is, the keys from F1 to F12 are programmed to run specified applications and I can't use hotkeys in Tibia because of this. Can anyone help me here?

Probably at the same level as the spacebar, should be a 'Fn' key, press that key then press the f1/2/3 ect. Ive taped mine down so I never have to push it.

I'm not sure if I understood you right. Do I have to press "Fn" and then when "Fn" is pressed push every key from F1 to F12? Cause if the answer is yes, then it's not working for me. The keys are still active. I was wondering if there is a way to turn them off. I don't want to be forced to install older version of Windows.