my powerbook seems to be louder than usual

Just recently my powerbook started to make more noise when it is running than it used to. So I have two questions. What is something inside that makes noise? I am thinking hard drive and fan. Its just a tad annoying because it used to be perfectly quiet. So I am worried something could be wrong. When I had a problem with the logic board like two months after I bought it, and it took a real long time to get back to me, I complained and spoke to a supervisor who said if I ever have a problem, they would replace it. So I may do that...

well, if you can get a brand new powerbook, then back up your stuff and just get it

What type of noise? I have a 15" aluminum G4 and the only noise I've ever heard is from the occasional CD that is not balanced properly. Makes a **** of a racket. Does the 15 have a fan? I've never heard it.