So I bought this pc from a buddy and when i got it it was pretty dusty. I ignorantly barely cleaned it and have been running it for about two weeks. Last night it started making a buzzing sound so i tried to move the pc to see about taking the side panel off and the second i moved it a little bit the sound stopped. This happened for quite a while until i started to tap it. At the place where I tap it, (top right of the motherboard, above the hard drive bay), i also tried applying pressure to it and once i put enough pressure down the sound also stops. i have to press hard though. I took off the side panel and checked to see what was wrong but nothing is where i am pushing down? I also cleaned the PC very well in hopes to quiet the fans and stop the noise. The noise did stop for quite a while and the fans got very quiet but recently started getting louder and now the sound is back. I will try to get a soundclip up soon to see if that helps. Thanks.