computer noise. help me fix it please

[TinStar]

My wife's computer is making this noise. It's somewhat sporadic but it seems like it is happening more often lately. She also claims that when it starts making this noise her internet starts moving slower. My guess is maybe the hard drive is starting to fail as it seems like the noise is coming from the area where the hard drive is. You may need to turn your speakers up a little bit to hear it. Any ideas?

[youtube]http://www.youtube.com/watch?v=qCqvKQ4uQgU[/youtube]