'R, how is old is this computer?'
'Couple of years.?
'That's what I thought.'
The fan has started rattling. I can't remember taking the case off and cleaning it. That might help. Instead of the whole case coming off, just one side comes off with only a couple of thumb screws holding it in place.
Was it dusty! Earlier I had asked for a can of compressed air at DSE, but they don't sell it, much to my surprise. I recall checking somewhere once before and the cost was about $20, for a can full of nothing but air. I can't be bother taking the car out to the big hardware store. I will do as I have in the past and use the vacuum cleaner and a brush.
Interesting, under the fan blades are fins, only seen once the dust was brushed and sucked out. With the side still off. I plugged it in and started it. The rattle was still there. Switch off and switch on and I held the fan blade still, but still the rattle was there. There must be more than one fan. I think the one I cleaned was the CPU fan.
I put the box on its side and ah, there is another fan at the top, facing downwards. It too is dirty. This is the power supply fan. I unscrewed the four screws holding the power supply unit in place, unscrewed a guard and the fan dropped a bit and I was able to wipe the blades clean. It was a bit fiddly to get the fan in position and screw the guard on at the same time, but with the help of metal skewer, I managed. All back together now. The noise has stopped, yay.
Hang on, the noise has stopped because the fan isn't working at all. I judged it time for some serious technical intervention. I whacked the side of the tower and ever so slowly the fan started to move. Well, at that speed, it is not going to cool anything. I wonder as the machine warms up will the fan loosen up, and that it what happened and it is quiet now. Whether it starts again once the computer has been turned off and on is another matter. I certainly see it as a temporary fix but this video was interesting. Peel back the sticky label in the centre of the power supply fan and put a few drops of sewing machine oil in and make sure the label re-sticks.
Or I may just take the computer to the doctor. I did check the receipts and it is five years old, but was upgraded last year.
Warning: Make sure the power is always disconnecting before fiddling in the box and if there is a switch on the power supply, turn that off too. There can be considerable power stored in that part of the unit. In fact don't do as I did, unless you know what you are doing, leave it to an expert. I did not not know what I was doing but I never do. Pull it apart and see what you as an amateur can do.