I have had my macbook pro for about two years and just last week the fan got increasingly louder. I tried a couple of things and found that if i take the battery out, the noise dies down and the computer is back to it's quiet self. If I put the battery back in, in about a minute or two, the noise comes back. The battery still holds a charge for about 45 minutes. Any suggestions? It is really loud and annoying. Thanks.