This is what you need to do, if your microphone does not work after upgrading to Windows 10. However, you’d still hear an echo once this issue is resolved and the echo might get resolved with an update.
Navigate to : Control Panel > Hardware and Sound > Sound
On the Recording tab, disable and then enable your Microphone listed.
Press the Windows key and type “Microphone setup”
Scroll down to the section that says Microphone and press the Get Started button
In the dialog box that appears, check if your speech input is being recognized by Windows and your microphone and click Finish once done. You’re all set to start using your microphone!
Hope this helps! 🙂