Keyboard Issue after upgrading EFI firmware Update

Hello friends..

I recently upgraded my 13" macbook pro (early 2011 model) running on Yosemite version 10.10 and had upgraded to Yosemite version 10.10.3. Also I have upgraded EFI firmware 2.7 from App Store update currently running SMC version 1.68f99. Everything went well. However, i discovered that slash and question mark button stopped working. Then again i tried to re-install by manually downloading firmware from Apple Official website. When I try to run the program it says this software not supported on this machine. Please advise what can be done to make my SLASH button key to work again. I am very new to MAC. Thanks