This article is focusing on the Realtek Audio card and disabling 5.1 or 7.1 surround sound so the recorder can correctly capture your Computer Audio:
1. Open the Control Panel by pressing the windows key or the "Start" menu and typing Control Panel and then clicking on Control Panel:
2. Search for realtek and then open the Realtek HD Audio Manager
3. Your particular Audio Manager window might look different but you should make sure that "Speaker Configuration" is set to "Stereo" and any check box like "Virtual Surround" etc are unchecked.
There are also other settings that might cause issues if you have a gaming computer. In that case you'll have to explore some of the settings to see if you can figure out what feature is causing the problem.