Hello,
Hold down Windows + R keys, type in mmsys.cpl and hit enter. Then go to the Recording tab. Do you see the Microphone? If so, please make sure it is not disable (you can right click to enable it). Also make sure it is set as default device. Then double click on the microphone, go to Levels tab, make sure it is not muted.
Go to Windows Settings > Privacy > Microphone, make sure allow apps access is turned on.
Install audio driver from computer manufacturer website. If you need help finding driver, please type msinfo32.exe in the search on the taskbar and hit enter, then share a screenshot of the pop up please.