Have you cleaned your PC lately?
My wife’s computer has been making some noise the past couple weeks, nothing major just slight vibration but it gets annoying. I had some alone time this afternoon while no one was home (read: my 2 1/2 year old wasn’t here to steal the parts) and I took apart the system for a good cleaning.
After going through a full can of air cleaning everything out I’ve decided I need to find a cheap air compressor as I think it will do a much better job than constantly buying cans of air. The system is now running as quiet as it was when we first turned it on. So consider this a friendly public service message to clean out your computer.