Windows 10 microphone problems?

I have the problem with my Win 10 laptop that the device thinks it has connected an external microphone, which is not the case. So if I Skype or something like that with the PC. Will, the partner hears nothing. Switching to the working internal microphone, it doesn't let me use the taskbar either. What can i do there?

Under "Sounds" / tab "Recording" you can select the internal microphone as the default. To do this, click with the right mouse button on the corresponding symbol and select the corresponding option.