Friends Can Hear Sound From Computer Through My Mic

[Nojus Bartusas]

Hey! I've been having this problem ever since I got a headset for around $30 or so - they're the SADES SA-708. The sound quality is great and all, just my friends get really, really frustrated when they can hear my game sound or a YouTube video playing in the background. I have found no solution for this...
SPECS -
i3-4000m 2.5ghz
NVidia gt 740m
8GB RAM DDR3
VIA HD Audio Sound Card
(I have a laptop)

 

[sizzling]

Turn your mic gain down

 

[Nojus Bartusas]

Turn your mic gain down

Mic gain? What?