Check all of your event sounds in the Sounds & Audio device properties in the Control Panel. Try all the sounds assigned to events on the Sounds tab and see if one matches what you hear.  Typically it is the one called Complete Navigation or Default Beep that triggers a lot.

Yes, I have recently noticed the same thing. I would describe it as a cross between water dripping and the sound of closing the CD tray. It occurs regardless of speaker volume and I don't even know if it's coming from the speakers or from the hard drive, but I do know that it's annoying.

Hi Chris - I've not be able to fix the problem - have you?  Let me know - I would appreciate the help.  It doesn't seem to be the volume.  Thanks!

Whoa, Chris - you have had a tough time!  This is my second Dell product and I've really not had any problems at all.  Actually, I've enjoyed them.  I have always been an HP fan but decided to try Dell.  I don't think the "dripping noise" hinders my machine - it's just annoying.  And, by the way, it just started making that noise about 3 months ago (bought it in Apr/May, 2005 along with a desktop).  You are right about one thing - I dispise calling, punching numbers to get to where I'm going then talking with someone who you cannot understand!  But, I think that's everywhere.  tt

I think I may have finally fixed the periodic clicking/crackling/crunching/water dripping noise that occurs on my Inspiron 6000. I've heard of others who have this problem too, so here's how I fixed it (after countless hours searching, emailing, and messing around):

The noise apparently stems from the Hitachi hard drive (mine's a 5400 60 G), and is a result of the heads parking/unparking, which is a power-saving feature of the Hitachi Travelstar drives (i.e. it's suppossed to happen). But it's really annoying, and happens much too frequently for my liking. Luckily there is a way to disable (or at least minimize) it. This probably decreases battery life, and slightly increases regular operational hard drive noise but it's worth it in my mind to get rid of that awful clicking noise.

Hitachi has a download called the Feature Tool, which you should easily be able to find from their website. You have to make a boot disk or cd with it. If you have no disk drive and need to make the boot cd, as I did, you need to have a burning program that can properly burn disc images (.iso files) to cd. You can't just burn the file as data or it won't work as a boot cd. Anyway, once you reboot to the cd drive and get the feature tool up and running (there's a guide on the Hitachi site which explains how to get through the first couple steps), there's an adjustable feature called APM (Advanced Power Managment). Crank this APM up for maximum performance (minimum battery life). Reboot and presto. I haven't heard the click since, and everything else seems otherwise normal. I'll let you know if I encounter any problems, but for now I can concentrate again in peace.