How to re-install deleted microphone device in windows 10

[rpspks]

No audio on Acer laptop. Somehow the microphone device was deleted. The volume shows 100% and speakers are Realtek high definition.

 

[rpspks]

After many hours of research I answered the question. It seems that an Intel audio driver was incorrectly pushed to devices via Windows Update in January 2019. To fix it see the link below.
https/blogs.msdn.microsoft.com/matthew_van_eerde/2018/10/12/if-windows-update-sent-you-intel-audio-controller-version-9-21-0-3755-by-mistake-uninstall-it/. I followed the instructions and it worked. I have audio again.