Hello... I have owned the Mac Pro for about 3 years and I've noticed recently that it's starting to get louder than usual. My guess is that dust has gotten into the fans. Is the best thing to spray with compressed air in the front and back to get out as much dust as possible or should I open the case and get rid of dust that way? I've also noticed some buzzing from the back next to the power plug, which I don't recall being there before. Is this normal? Thanks!