This looks like a winner.
"Just in case it doesn't, to change the sound device on Windows, go to Control Panel, Sounds and devices, then on the audio tab change the top 2 (playback and record) to your new sound card and that will stop it from using your motherboard sound.
If you use Vista then it's Control Panel, Sounds and devices, then on the playback tab click your new card and "set default" and on the recording tab click your new card and "set default"."
If not, you should be able to turn it and raid off in the bios.