Ping noise from hard drive area

My 2-week-old Macbook Pro 15" has been making a "ping" noise coming from the top left corner, I imagine from the speaker on that side. It is the computerized "ping" apple has under its list of sounds in the Sounds panel. It is not affected by volume settings, it is not loud either. The noise seems to be random, sometimes several times a minute and sometimes a few minutes apart. Re-booting helps temporarily. It seems to be connected to the hard drive somehow, as I often hear noises coming from the hard drive around the same time. I have not noticed any performance problems but the sound is annoying when the room is quiet. Thank you for any help!

Macbook Pro 15" 2.16 GHz C2D Mac OS X (10.4.8)