I need help!!! my headset is buzzing lol

Question

I recently bought a mikomi USB Stereo Digital headset from Argos (lol dunno if this post is Amercan or not..) for £17.99 anyways I've had it for a few weeks and it has been working fine until today. When I plugged it into the USB port I got a constant buzzing through the headset which seemed to be effected by the mike not to sure... I tried plugging it into different ports with no change at all. This model I gather is supposed to be plug and play so I don't think I need any drivers or whatever. Anyways would appreciate sum help thanx.