A couple of days ago I noticed that this function no longer works. I tried using the Windows Recorder and also Adobe SoundBooth. None of these pick up a thing, so I know it isn't an Audacity problem.
The next thing I did was to download the K lite codec pak and install that, in hopes of fixing something broken. That did not help.
After finding that I have a Biostar TF520 A2+ motherboard, I downloaded and installed the latest onboard audio driver for it. That still has not done the trick.
I checked the Realtek site, and they caution you to download drivers from your motherboard site rather than them. Especially since mine is well over three years old, this makes sense.
How can I tell if the Realtek component is defective? Maybe I need a new audio component?