In a terminal try running "asoundconf list". That will attempt to list installed sound cards. Also try "asoundconf reset-default-card". Also right click on volume icon on panel, select properties, and see if it is listed and the correct track is selected. I always have to change mine to front. It is usually on PCM.
"The only thing necessary for the triumph of evil is for good men to do nothing." Edmund Burke
install the latest alsa-base 1.0.15 in a terminal type cd /usr/src sudo module-assistant update sudo module-assistant prepare sudo module-assistant auto-install alsa sudo shutdown -r now look for the type of chip (in a terminal) with cat /proc/asound/cards head -n l /proc/asound/card0/codec* search in file /usr/share/doc/alsa-base/driver/ALSA-Configuration.txt the chip edit file /etc/modprobe.d/alsa-base , on the end type options snd-hda-intel model=STAC9205/9254