Audio from headphones leaks/bleeds into microphone

[Flukeworm]

I have a Trust GXT 340 7.1 USB Gaming Headset. My problem is that any and all audio from the speakers on my headphones is picked up by the headphones' microphone. This means that when I'm on Skype, anyone on the other end can hear music, game audio, themselves etc. The higher my volume is, the more the microphone picks up.
Just to be clear: It's not a matter of my microphone transmitting my computer's audio(i.e. sound mixing, 'listen to this device' etc), but the actual sound from my headphones 'leaking' into my microphone.

Any light on this matter would be greatly appreciated.

Edit: I'm running Windows 8.1 x64

 

[Flukeworm]

I just solved the problem. Apparently, the microphone boost on the previous(onboard) recording device(which was at max) somehow influenced the microphone on my headphone device, causing the microphone to be unreasonably sensitive.