I also tried contacting Lenovo and looked up on their forums, but it seems they only offer to replace the whole keyboard which is not an option for me. I have tried various solution on the internet, like for example trying different combinations also attempted to disable the FN key entirely but nothing works. (except my battery which may randomly switch states and turn my computer off at random times, but that's another issue.) The cause of it getting 'stuck' in such way is unknown, but I am almost certain it is not due to physical damage as everything else works perfectly fine. The FN key on my Lenovo ThinkPad has been non-responsive since some time last year and is just showing this constant green light which never turn off except when the laptop is turned off.