Reverse FN Tast

[ANSEL]

I`m running win 8.1. Now I have disabled the drivers for the mouse( big trouble with that)
so now I have to reverse the FN tast (done with Logitech drivers before) can`t figure out
how to do that ( I have done it before don`t remember how) Please some little help

 

[ANSEL]

I have maybe solved it with a 64 bit driver, but any information's about
this problem is still wanted.