Ya know... get that can of compressed air out and give 'er a good hose down. How often? Also (if you want) give the specifics of your ritual, if any. This came to mind because just a few days ago I noticed my fan running faster/louder than usual. I'd been neglecting to do this for quite some time, where I used to be very good with it in this regard (twice a year). I opened 'er up and beheld a TON of dust... the worst it's ever been. I personally blow as much out as I can with my own lungs first, and then save the can o' air for the finer detail. I take out all the drives, cords, cards (i.e. memory, PCI) too. Now she's running nice and quiet again. That was the first time I actually heard my fan work harder/faster, because it was over-heating I reckon. By the looks of how much dust was caked all over the fans & power supply, it was understandable.