If you've ever wanted to record only the sounds being outputted by your computer, here's how:
1. Right click the white speaker icon within the notification area.
2. From the menu, click "Recording Devices".
3. You should now be looking at a new window, titled "Sound", specifically you should be on the sound tab. From here, right click within the recording-device display box.
4. From the menu, click "Show Disabled Devices".
5. Double click "Stero Mix".
6. A new window should appear, titled "Stereo Mix Properties". Locate the text "Device Usage", and from the dropdown menu, select "Use this device (enable)".
7. Click "Ok".
8. You should now have the window entitled "Sound" selected again. From here, select "Stero Mix", and click the "Set Default" button.
You should now be able to record sounds produced by the computer speakers (i.e. a youtube video, system sounds, video game sfx &c). This is also useful if you would like to stream audio in high-quality via anything that uses a microphone, like a computer game or a communication application.