laptop noise

[MusashiX]

I'm starting to hear a loud noise from my laptop. I never noticed it before, but now I can't help but notice it and it's irritating me to death. Now I'm thinking it's the hard drive, but I'm not sure. What can I do to reduce this noise?

 

[AC]

could it be the small fan that some laptops have?

dust in the bearings can cause it to rattle/grind