Can you please try it in a new (temporary) Firefox profile and see if the issue is still present? See this article to know how to create a new Firefox profile. Please report back the results.

Also, does this happen on other browsers or is it just Firefox?

It ONLY happens in Firefox. It is driving me crazy. Its like a "light tinkering of a bell" whenever I scroll with my mousepad.

I did what you said and it didnt help. this clicking sound is driving me bananas

thanks again, but let me know if u have any other suggestion

If a new profile has the same problem, it's an indicative that it's something external to Firefox that's doing this. As you can probably imagine, this doesn't happen to me or any one Firefox user I know of. This may be caused, then, by a plugin (go into Tools > Add-ons > Plugins to manage them), or any other thing in your computer. Even the drivers of your mousepad.

Of course, if I was able to hear the sound, maybe I'd be able to identify where it comes from. Is it a Mac OS X sound? Maybe it's some kind of "error" that's being reported to the OS and that shouldn't be happening?

In any case, try reinstalling Firefox. No data will be lost, so don't worry.

I have the same problem on my mac (imac). It doesn't happen with Safari. I am running Firefox 3.5.15 and yes it is driving me nuts so much so that I no longer use Firefox. Safari is my current app.

"Safari is your current browser" to be correct. "App" is an abbreviation of "application" and I'm sure you don't use just one application at a time.

In any case, have you read what's above?

Yes I know what an app is and what a browser is. Yes I have read what's above. This is a relatively recent phenomenon and very annoying. As I said it doesn't happen with Safari or any application, only with Firefox. Thankfully, it hasn't reappeared for a couple of days. Naturally, Murphy's law will prevail and it will reappear.

It started a couple of days ago and this morning figured out it wasn't my IMAC, but the browser, as it doesn't happen in Safari. I just don't like using Safari. :O(