If these are your headphoneshttp://www.hyperxgaming.com/us/headsets/cloud-stinger-gaming-headset?partnum=HX-HSCS-BK/NA&ktc_campaign=
I don't see any mention of surround sound.
If the headphones only have a 2 channel analog input they can't accept 5,1 channels from the PC. If you set the PC to 5.1 you will only hear sound when the front channels are active. You will loose all center channel dialogue and surround effects. Set the PC to 2.0