how to redefine a key on my window 8 (Lenova) key board?

I have an Lenovo window 8 machine (call twist), the function key row on the keyboard now require to press a "function" key and the key (2 key at the same time).   the "f8 key" and the key to turn off the Wi-Fi connection is the same.  as you know, we use f8 key as the debugging key to step through a program on visual studio (vb.net, etc).  

we need to find out a way to disable the "f8" key posisiton that actually disconnect the Wi-Fi.

pls tell me the steps need to do this sort of things?

thank you