One thought!
In Device manager, Click on the + sign near Sound, video and game controllers and see sound card listed.
if not, it could be listed as unknown device/other device. Right-click on the entry for the "unknown device" and then select "Properties". In the "Properties" window, click on the "Details" tab and let me know the string displayed under Device ID.
For example: PCI_VEN13782 etc.
This will help you to find the manufacture and name of the sound card. ANd you may find driver links using the device IDs
May be it helps