Realtek disabled Stereo mix?

[any ANONYMOUS forum user]

Realtek disabled Stereo mix. I've looked at a lot of possible solutions for this problem, but have come up empty. I just started using Audacity, and during my first session the Stereo Mix worked perfectly!

I was thrilled, until I tried to use Stereo Mix in my second session, when the recording didn't pick up anything. My volume for stereo mix is all the way up, I have stereo mix selected in the volume controls, and it's enabled in the preferences (I tried a few combos). I even tried going straight to the soundcard (it's Realtek) and seeing if it worked. It was still unavailable. This isn't the first time too... the exact same thing happened with Gold Wave. This is very frustrating! Please help!