Firstly check the bios (press del lots traight after your computer boots, and under advanced there should be an option to enable/disable your integrated soundcard). As for the drivers, its best that you recompile your kernel with the right drivers. This is kinda tricky for a noob but not that hard. I found the soundcard for your motherboard, its a ADI AD1980 SoundMAX 6-channel CODEC with a S/PDIF out interface. After a bit more searching I discovered it uses the AC'97 chipset. The alsa driver for this is called intel8x0.
To wrok out how to install this I suggest you read the gentoo alsa guide, and the gentoo kernel compile guide (start at the default: manual configuration section).
- kernel compile guide
- gentoo alsa guide