Hi Trey,
As Shawn says, it may be that you need to press another key prior to F11 in order for it to work. Is your keyboard one of those where the function keys have a dual purpose (i.e. they also have text/symbols on them with functions such as Open, Close, New, etc)? If so, there should be a key labeled F.Lock (or similar) with a status light somewhere on the keyboard. Check its status - for function mode this indicator should be off whereas for F mode it should be on.