I have purchased a second hand PC (8 months old) and the fan seems louder than I am used to! It's not a clunking or erattic sound just fairly loud! Any advice would be appreciated!

Answer:
I had this same problem with a fairly new Personal computer. It was under a year old. I talked to a lot of techs from the company and nothing they recommended worked. Finally, I took the side off to have a look and noticed the dust. I good cleaning solved my problem.
Answer:
I'm going to take a wild guess that the answers telling you to clean the fan etc aren't going to work for you, because something tells me you wouldn't know how to fiddle about inside the case. I might be wrong but in case I'm right, just go to your local Computer repair shop (NOT a big shop like Dixons or Personal computer World) and just ask them to fit a quieter fan or a new heatsink with a quieter fan.
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if the sound is coming out from your power supply fan, you’ll need to replace the power supply

yes you can slow down your processor work rate by applying a technique called throttling - you will have to get into BIOS , however it will slow down your system performance

Answer:
Open it up and clean it as suggested. In many cases the bearing is damaged or worn. You could always buy another. They are fairly cheap.

Try a tiny Vaseline on the bearing before doing it all up again.

xx VP

Answer:
Just change it, it's very easy. See below Quiet fan.
Answer:
try cleaning it