Microphone Noise - Help

When running certain applications or sometimes seemingly out of the blue, my Hard drive (or soemthing) makes a loud buzzing noise that sounds like complete static through my Mac's built-in microphone.

Is there a way (without getting a new mic) to tell the computer to cancel such noise, or reduce such noise as much as possible?

Thanks

 

yeah, that was my fault. I saw the other forum and I said to myself "Should've posted it there." So I did...