Audio Not Working On Ubuntu?

my sound was working just fine until i installed the Gstreamer codecs and vlc media player. now it gives me this message everytime i try to change the sound level. there is no sound at all. i uninstalled the codecs and vlc media player and it still wont work.
The volume control did not find any elements and/or devices to control. This means either that you don’t have the right GStreamer plugins installed, or that you don’t have a sound card configured.
You can remove the volume control from the panel by right-clicking the speaker icon on the panel and selecting “Remove From Panel” from the menu.