I've had a Dell XPS420 for a couple of years. Recently the cpu fan revs up a couple of times each week. I cleared dust from the fan and heat sink. The fan operated normally for a while, but now it revs up again. Any thoughts?
Is it random or repeatable? Can you make it do it or does it just do it when ever. Usually is an indication of a heat issue.
Pick up the free program Core Temp and set it to run in your task bar to monitor your Cpu temps.
There is the possibility that the thermal paste between the heat sink and CPU is breaking down and needs to be redone
Here is a link on that procedure as