Recording computer game?

I want to record when i play on my computer but i do not know how. Witch program and how to use it? I got fraps but i do not know how to record sound. Fraps is good but when i choose to record sound it does not. And when i choose another option then it records whats happening outside of the computer via my mic. How do i make fraps record sounds of the game like here http://www.youtube.com/watch?v=AkfQ9key-x0&feature=related Any help?