Chainsaw sound coming from PC.

[Praetorianz]

Yesterday the whole day there was this chainsaw-like screeching sound coming from my PC, I opened the box and it sounded like it was either coming from the CD rom drives or the harddisk, even though there are no cd's in the drive. Today, the chainsaw sound comes up frequently, and sometimes it kind of stops, and then it comes up again. Its really driving me nuts. And the funny thing is, I'm not experiencing any problem with the computer itself, the performance is just as it has always been and I can do everything alright. Does anybody have any idea what it is?


Thanks a lot.