Hey, I have the same sound card and had the same frustrating problem. I discovered that I needed some of the Realtek AC97 drivers loaded for my card. (Realtek made the IC or something like that.) Go to http://www.realtek.com.tw/downloads/downloads.aspx
and under Downloads choose Computer Periphrial and Multimedia ICs and then AC'97 Audio CODECs. For me from here, I chose the ALC650 because that's what is on my motherboard (Asus A7V8X) and downloaded the drivers. Installation is kind of a pain but if you read the documentation carefully you can figure it out. Unfortunately, not everything is working with my sound yet, but hey, at least I have something. Hope this helps you.