yesterday i updated my Ubuntu system from 12.10 to 13.04 but since then my audio card doesn't work at all. With the previous Ubuntu version it worked fine. The sound card is recognized by the system (sudo aplay -l) but the sound list in System Settings - Sound - Output etc.. is empty. Tried also to install Realtek Linux Driver from http://www.realtek.com.tw/downloads/downloadsView.aspx?Langid=1&PNid=14&PFid=24&Level=4&Conn=3&DownTypeID=3&GetDown=false but with no result. Please HELP!!! :)
Thanks for your answer.
I'll try this solution next time (hope not).
Few days ago i followed the Sound Troubleshooting Guide below https://help.ubuntu.com/community/SoundTroubleshootingProcedure
and the sound worked when i run
and restart the machine.
this may solve your problem: http://ubuntuforums.org/showthread.php?t=2139589.