Interchanged function keys


I am using Lenovo laptop. I have issues with my keyboard, I think that specific key functionalities have been interchanged especially the function keys(f2,f3,f4,f6,f7,f8,f9,f10,f11,f12). Eg. F6 key in my laptop used to be mute but now f7 key became mute key and if I press f7 key while using browser a dialog pops up suggesting to 'turn on carat keys'. My keyboard used to be fine, last time I used my function keys was around 13 days(or less) and I discovered this tech issue yesterday. I don't know what to do. Please help.


Kiruba Rathinavelu