My PC started suddenly to buzz because of vibration. It comes and goes at random given times and if I give a little tap on the side or on the top, the buzz goes away.
It might help to say that I had my power supply swapped out because of its faulty fan, it was all done under warranty and I didn't remove the power supply and I didn't put the new one back in, it was all done at the shop.
When I got my PC back, it didn't buzz or vibrate at all for about 3 weeks. During that time, I didn't do any modifications or move the PC.
I opened up the side to listen where the buzz is coming from and I'm pretty positive that the sound is loudest in the front where the DVD reader is (no disc in drive though). It doesn't seem like the fans are causing this issue. I only have 1 case fan at the back working at 500 RPM.
The thing is, the slight buzz sound doesn't annoy me that much but the vibration my PC sends throughout the whole PC table is quite annoying. By just placing my hand on top of the table, I can feel slight vibration/humming going through my hand.
I've been thinking of buying some kind of a mat to put under the PC in order to dampen the vibration although I have no idea if it will work.