My Inspiron 300m is making a loud noise and I think it's coming from the fan. Is there a way to confirm or verify where the noise is coming from?
Run Prime95 and see if the noise speeds up -- if so then it is certainly the fan.
It can't hurt to shoot some compressed air in there, and see if that helps clean anything out.
The most common source of laptop noise are misaligned fans. If the laptop is often overheating the fans have to work harder and can/will eventually collapse.
Depending on the type of sound it may also be a vibration from a loose hard drive or CD/DVD-ROM drive housing. Normally this sound is a slighter hum than the sound of an unbalanced fan.
Turn the laptop around and press lightly in different places until the noise varies. If it does, identify the spot and try to see if there is anything loose. It could be a screw covering the hard disk, a battery or some other component.
I had this problem with my old Latitude 2120. It would make this horrible noise, overheat, take a nap. I thought I would have to replace the fan, had it open, and bam..there it was. A small piece of plastic (I still have no clue where it had come from) was inside of the fan case. Removed it and bam, that fan worked for the rest of the computer's life. So I'm seconding the above comment. (I can't leave a comment as I'm still new yet.)
So maybe take it apart and give it a look. You never know. I hope this helps, and if it doesn't then I hope you find the answer you're looking for!