I am using a Realtek High Definition Audio card (Built in the Motherboard: Gigabyte 990FXA-D3)
So recently I have been informed that, whenever I talk on Skype or any other software, I have about 20%~40% Stereo mix.
I tried muting all my devices physically, but they kept hearing me, I shut down all the sound devices by software, all but the Microphone and the speakers/Headphones.
They Kept hearing. (Stereo mix was off)
So I muted my device (Software vise) and they stopped hearing it.
Then I tried to use a USB microphone and the problem was gone.
So when at it's purest, My Speakers/Headphones are somehow hooked with my Microphone via Software.
The problem is with the Sound Card, since the USB Microphone had no problem.
I might have to mention that in the past, I used Virtual Audio Cable, but I removed all the devices and Software.