This is how to select and check speakers, headphones or a headset and the microphone in Windows.
Choose speakers or headphones
In the taskbar, click the speaker icon.
Next to the volume slider, click the arrow and choose the output device you want.
Check the volume.
Choose and test the microphone
Open Start › Settings › System › Sound.
Under Input, choose the microphone you want.
Speak into the microphone: the level bar should move.
No sound or microphone not working
No sound: Right-click the speaker icon › Troubleshoot sound problems.
No sound via an external monitor: Check whether the monitor has speakers at all. Otherwise choose a different output device.
Microphone doesn't work in Teams, Zoom or the browser: Open Settings › Privacy (or Privacy & security) › Microphone and allow access for apps. In Teams, also choose the correct microphone under Settings › Devices.
Headset not recognized: Unplug and plug it in again or use a different USB port. Then install Windows updates and restart.