Problem with microphone model: Razer Kraken X Lite 7.1

I bought a headset yesterday but when i proved it, the microphone didn't work. The headset's model is a Razer Kraken X Lite 7.1, the headset sounds great but when i try to talk, the microphone just detect the sounds of my PC, that means: all sound that get out of my PC (like music, videos, etc.) is reproduced in my microphone. I think that the problem could be in the adapter cable since these headphones come with a single input and an adapter for a desktop PC, i know that a lot of people have had this problem with this type of headsets before but actually i don't know how to fix this, maybe another adapter? I have Windows 7 64 bits, if anyone knows how to fix this, i will appreciate that