Did you just reinstall Windows on your computer?
If you have, then you need to install the drivers in the correct order, or some devices may not install properly. You can check the link: http://dell.to/vQAp1f to know the installation of drivers in correct order.
You can install audio driver for your computer from the link: http://dell.to/V3nzFc
Steps to download driver:
See if it works. If the issue still persists, you can try installing the driver: http://dell.to/WztykE and check if it works.
Please share the findings.
Thanks and regards,
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