A buzzing sound in my newly built PC

[GameQari]

Essentially, I have a loud high pitched noise when I have my mic on. I made this new Pc so I could render and upload League of Legends videos. I've been saving up for 3 years, so it was kind of a bummer. I know it's not the headset, cause it works fine elsewhere.

Here is an example of the noise http/www.youtube.com/watch?v=AdgBtZubMbg (It's a gaming video, and i turned it down so that the sound wouldn't be so annoying, but if you turn the video sound up, you'll hear it.)

Anyways, I rubbed my few brain cells together, did my research, and have come to find that it's probably interference. I'd buy a sound card and be done with it, but my headphones are Plantronics Gamecom 777's which are USB headphones that emulate 5.1 surround when I use the USB. I tried using the analog, and the same issue exists, but in a different way.

Some facts: It only happens when I turn my mic on, the noise is not present with it off. I have tried evey USB port on this thing. I have a coolermaster Enforcer case. I did notice that it is very visibly reduced when I place my whole hand on the case, not just a finger or two.

I was thinking, it's interference, but how do I go about resolving that?

Any ideas?

 

[I]

What if you use an add-on sound card only for mic input, or will the game not allow a different sound device for mic vs output? I've never tried it but thought there was some Windows mixer feature that could integrate two different sound devices logically.

 

[GameQari]

So, first of all thank you for your response. I don't have an add-on, and I don't think it would solve my usb problem because on the gamecom777, the distance between the speaker and mic cords is just over 3 inches where they connect. However, what I did was plug in the USB for the headset in the front jack AND plugged in the microphone seperately in the analog spot and it works.