How to change Function key behavior without go to bios setting?

My Fn key is damaged and its behavior is now as multimedia key.

I can't use Fn key. I can't use F2 and F12 key during boot for enter bios menu.

Now in my mobility center there's no Function key setting availabe. ( In mobility window there is only main 6 options availabe but no 'customized by dell' > fumction key setting..

Now I am stuck..

Any suggestion?