Hi, i have a problem, the fan in my computer keeps speeding up and slowing down, then it does it for longer, i had this problem before and Fujitsu ended up replacing around £600 worth of parts, thank god for insurance! Any help please?

Most modern systems have some form of fan RPM control where they'll speed up and slow down according to the thermal dissipations requirements. For instance, you introduce heavy load to the CPU and thus it needs more cooling so, it's fan will kick it up to a higher RPM until things are at a lower temperature (whereby the fan would drop back down to a lower RPM). Are you sure it's not supposed to be doing this?

Yes it is but i didnt know why it was doing it all of a sudden. I have now realised, it was because my mother had put the sub woofer over the cpu fan outlet. Silly woman, its stopped now i moved it!

Well, theres another one solved, as quoted by Kimsland.