Every couple of minutes the fan comes on and runs loudly - can I stop that?

[computerhapless]

I have an older HP Pavilion desktop.  Every few minutes the fan comes on and runs - loudly - then goes off for a few minutes, then starts up again!  Why is it doing that, and can I stop it somehow? It is very annoying.

[banhien]

@computerhapless 

Normally, machine has a heat sensor to control the fan and the fan will kick in when required (machine/cpu getting hot) and it will stop when machine cools down.

Your machine is a bit old therefore you may only notice the fan noise recently. Option:  find down which fan, CPU fan or case fan and replace it.

Regards.

[computerhapless]

Thanks for your comments.  After I posted my question, I read the HP help page - it suggested cleaning the inside of the computer. So I took the side off and, sure enough, there was a lot of dust inside.  There is a fan near the center of the machine, and it was really coated with dust, so I cleaned it off with a small hand-held vacuum - and the computer has been running quietly ever since!