Jon, assuming you haven't found the driver yet, we'll need to get more information as to what's the actual audio chipset being used by that cryptic MS-6564 audio controller.
You could use Everest Sysinfo to help identify the device first. If not, using Windows' own Device Manager will also do, although it may not be easy if you're not very experienced with the tool.
Check the Device Manager, click the audio controller properties -> details -> device ID (not very sure of the exact sequence of steps here), but you should see something that looks like this:
If you could post the above PCI Vendor_ID string, we could have a better chance of finding the correct driver.