I am using ubuntu 12.04 and I made an upgrade last time and asked me to reboot the laptop. after restarting the laptop, I realized that my keyboard is not working at all [I am currently typing from on screen keyboard].
I tried to do sudo update and also sudo upgrade. Moreover, I tried to log in as guest to see if the keyboard is working; however, it is still not working.
is there solution to make the keyboard work again as it was before. thank you