Hi,
Here are some suggestions on how to troubleshoot that issue.
- Check Device Manager first and see if your Sound card is listed normally.
- If it's listed normally uninstall/reinstall it that may help.
- Once you've uninstalled the sound card driver from Device Manager reboot your PC and it should reinstall the driver automatically.
- Test the sound again, if you're using an external speaker try using a different speaker or a headphone.
- If all these will not work last resort would be downgrading back to the original OS or checking the manufacturer website of the motherboard for any sound card driver compatible with Windows 10.
- Your sound card is faulty if all these steps will not work.