For anyone having the same issue. I think I found out what the problem is, unfortunately theres no way to fix it.
Apparently theres a hard limit on how much power your USB sticks can provide all together, so my headset and the controller was using too much power for my motherboard to handle.
So I've been using a Razer Megalodon headset for a year now without problems, but now when I plug in a XBOX 360 controller the sound stops working on my headset.
Theres loads of threads on this page about the same problem, but I haven't found a real answer yet.
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So I've been...