As root in a console window /etc/init.d/alsa-autoconfig to create the alsa devices for the sound card then you should have sound again. When you re-start the volume levels for alsa will default to mute so also as root in a console window edit the file /etc/init.d/bootmisc.sh and add the line aumix -w 75 -v 75 to the bottom of the file and you will set the levels every time you boot.