It appears you have one of the following mobos:
K8N Neo4 Platinum
K8N Neo4
The MS-7125 part of the number you provided gave me a hit at the MSI website which I visited after getting a number of leads from Google suggesting MSI.
Assuming we have identified your motherboard, the audio portion is as follows:
Audio
• 7.1 channel audio codec RealTek ALC850
- Compliance with AC97 v2.3 Spec.
- Meet PC2001 audio performance requirement.
This much is common between the two motherboards referenced above.
Assuming you're running 2K or XP,
this should be the driverset for the audio portion of your board.
Hope that helps.
**EDIT**
If you're not confident this is the motherboard model you have, take a look at
this article if you haven't already.