noice on my computer was caused by a micro wireless receiver for my Logitech keyboard and was right next to another USB cable which may have also been located closely to audio on mobo. The USB input was on the back where all other usb cables were located. i read several posts here about removing and reinstalling
drivers, hardware, etc. I realized it had not always been present. I then tried to recall what had changed. I go back and forth between wifi mouse and keyboard w/receivers (Logitech) and wired keyboard and mouse-Microsoft Sidewinder and a Logitech G4. I game wired and enjoy freedom of wireless for all else. However, the noise has really turned me off now to using the wireless and have known for a while that security of wired is much better than wireless products. Still, wireless was very convenient and nice to have as cables werent attached. Both have their merits however, noice was caused in my case by wireless wave frequency interfering w/audio. This occured whether it was my Sennheiser cans or w/Bose spkrs. I hope this helps. Sometimes the most easiest solution is the accurate one. Think on it before ripping your hair out, deleting drivers and reinstalling everything as you can really mess your system up when all you had to do was unplug a tiny wireless receiver....good luck.