Dell Precicion 5750 - internal audio system not working

I have a Dell Precicion 5750 that is on a Windows 10. The problem I am having is with the audio. The troubleshooter failed to resolve the issue. Despite uninstalling and reinstalling the audio drivers, the problem persisted. I visited the Dell website and downloaded the latest audio drivers for Windows 10, yet the internal audio system remained non-functional, despite diagnostics suggesting no hardware issues.  Furthermore, I attempted to resolve the issue by cleaning the registry using CCleaner, but the computer continued to indicate no internal audio devices (microphone and speaker). I also downloaded the Realtek High Definition Audio Driver and restarted the computer, but this did not resolve the issue. The internal speaker does not work and it does not even show up as an option in settings and sound settings. Could you please advise on how to solve this issue? Thank you.