Win10 sound, or the OS specific equivalent is the muxed together sound of all playback devices. It's possible you have the microphone input being output in the list of playback devices. First port of a call would be to check which devices you have selected as playback devices.
On the windows 10 sound icon in the notification tray, right click, select playback devices. Ensure that only things like your soundcard, or relevant devices are playing back. Right click on unwanted devices and select disable.
Likewise, check the recording tab in the same window, and check that only the relevant devices are enabled.
It's always worth checking this on new OS installs or upgrades..
edit: also, under record settings. Double click your microphone, go to the listen tab, make sure "listen to this device" is un ticked.