In desperate need of help...Cannot get F4 to work as absolute reference shortcut

Hi Guys,

So I am completely stuck with a seemingly minor function of excel, but I am completely stumped. I simply cannot get my f4 key to work as a toggle for absolute references. I recently switched computers from a Lenovo X230 to a Lenovo T430 and in both Excel 2010 and 2013 my f4 key just doesn't work for absolute references. All the other functions keys work as they should( so its not an F lock) I have completely installed both versions of excel again. I have tried on both windows 7 and windows 8. I have no idea what to do. Does anyone have any ideas?

No the F4 key is functional. It works perfectly in other applications and even in excel for doing things like repeating an action. For some reason I just can't get it to work to do an absolute reference.