I have a refurbished Xbox 360 Arcade that I got a while ago (between 9 months to little over a year ago). I keep it laying on its side in my room. For the longest time,the fan would only blow audibly whenever I was playing a visually-high-quality game like Brutal Legend, Bulletstorm, Halo 4, Arkham Asyulm/ City or Ultimate Marvel Vs. Capcom 3. Since my brother put a cable box in my room and decided to put my 360 on top of it, I also have been hearing an audible humming that sometimes goes towards buzzing. And, after two and a half weeks of not playing my 360, and trying to connect a second controller for my guest, I heard a combination hum/buzz as I was setting it up and it was idle. Could it be because it was on top of the cable box? Or of dust that gathered around the system?