So your realtek worked??.. and if yes which way?? pls tell so if someone else has the same problem can find a solution.
About the sound.. the first thing that comes on my mind is that you should configure alsa.. so open a terminal and type
then type your root password
then use your arrows to navigate and press the m key on your keyboard to unmute the channels you need..
press escape when you finish and type on the terminal
hope that helps..