Horrible Digital Audio Noise Problem

[Runners_Dial_0]

Hey folks,

I'm posting in hopes to getting some help for serious noise problems in my signal chain, and I don't know what's causing it.

It's intermittent, and extremely obnoxious. Here's my signal chain:

SM58 --> XLR CABLE --> M-Audio FastTrack Pro --> USB Cable --> Laptop, running DP 4. Recording directly to the main hard drive.

I'm running two of these systems, and my guess is that it's the FastTrack, but... Two of them that can't be more than two years old

Here's the specs for the laptop: Mac OSX 10.3.9 / 600 MHz PowerPC G3 / 128 MB of Ram.

The audio I'm getting is riddled with really abrasive digital clicks, and I've got no idea what's causing it. If you're interested in helping, I've included a sample of the audio that you can listen to.

http://www.mediafire.com/?26ynyk1jmnn

Thanks in advance for any help!

-Chris