terminal and keyboard password ?

Hi everyone, and thank you for your time.

I have a Mac Pro 2.8 mid 2010 quad core. Updated the firmware from4,1 to 5,1. Unfortunately now I can't create a bootable USB drive. I followed to the *T*, on Apple's site how to creat a bootable USB, and worked every time, but now strangely enough when I enter all the sudo cammands it types the commands and all the processes go through, and then when it asks for my password, at that point the keyboard does not let me type in my password, or nothing ?