I have seen many complaints on the MacBook Pro hissing noises, be it from the speakers, the hard drive, or the screen as you say.
You seem to suggest that your MacBook is only two weeks old. If it is constantly having these issues, back up your data and return it to the store. I believe that Apple has a two week return policy. Even if you are a few days over, I'm sure that they will still help you out. Take it to the Genius Bar, and request a replacement. If it is a brand new Mac, they should replace it completely, instead of repairing it. A fully functional MacBook should not emit any strange noises. Let us know how you get on.
Used my MB134 for 2 weeks. and the noise drives me nuts.
1. Very strange hissing noise when using battery only. disappear if connected to ac.
2. High-pitched whine related to screen brightness on vista. gone if maxim brightness or back to leopard.
Anyone has the same problem? plz let me know how to solve it.