sound not working in dell optiplex gx1

I have mepis on a dell optiplex gx1 and sound doesn't work on it. I have tried the DSL distro live cd and sound works perfectly without configuring anything. I have googled on the internet and so far I found something for ubuntu here http://ubuntuforums.org/showthread.php?t=305269&highlight=gx1+audio but it didn't work for me. Can someone help me? Thanks in advance.