Hi Scott - you could have just described a "lazy" click that I occasionally hear coming from my PC case. It can happen once or twice per session and depends upon me accessing a particular software or the Internet or whatever, but I've never been concerned enough to narrow it down. I only started noticing it a year or so ago although that's not to say it wasn't there before. I just assume it's the noise of the HD needing to be accessed over a greater physical distance than normal every so often.

John