Noisy computer fan?

[Scarlett]

I am a bit worried- my PC seems to get noisier as the evening goes on. I am worried as it is getting a bit old but I'm in the middle of a dissertation and need it to survive! Is there anything I can do to quieten it down? I haven't really done much re. cleaning it- - would hoovering the back help this?
Thanks

[RAV1D]

fans can become uneven and get noisy they may get build up of dirt and dust on them or just worn out and unbalanced. try wipe off any dirt from your fan or try a vacume fitting with soft brush. they ain't to expensive to replace if it's just on it's way out.

[jomifl]

The ball races can get dry and produce a whining noise some time prior to total failure. Try a little light oil on the bearings with some WD40 to help it creep. Just a tiny amount should do it. A penetrating oil with teflon would give an almost permanent cure.

[jacksprat16]

the bearings are behind the centre name foil peel it off but try to put it back after don't use more than TWO drops maybe not that much see how much is taken up first

[jacksprat16]

but first get a can of "air blaster" and blow all the dust out from
maplins etc