Could it be because of the PC that you don't hear surround sound 7.1?

My buddy bought a Razer Kraken Tournament today and doesn't hear one

7.1 Surround sound. He installed the driver and also set it in his settings. However, surround sound works on his laptop.

I generally find surround in headphones totally pointless. My external sound card can also use Sorround, but I never use it, because I can't find anything particularly through headphones.

2 sound transducers = 7.1 not possible

You can of course download this terrible 7.1 software from Razer and then you have just simulated 7.1 sound (usually sounds much worse than without).

What's this? (2W sound converter)

"Terrible 7.1 software" that was good. I can only confirm, and unfortunately the simulated Sorround is also true.

Do you at least know what 3.5mm jack plug means?

Yes

Then describe me what that is.

Only 2 speakers (drivers) are installed in the headphones. For 7.1 you would of course need 8.

He has a surround headset

Razer Kraken has only 2.

Better not a real Sorround headset but the included sound card where you have to install Razer drivers and that the Razer driver software simulates Sorround Virtual. And if you think about it, then you will find that it makes no sense to buy a Sorround headset because you can also download Simulated Sorround software for free and convert it to virtual headphones with any headphones, and sound just as stupid in the process becomes like the actual gaming headset with alleged real Sorround function.

As I said: Almost every gaming headset offers an auditioned virtual sorround.