disabling all extensions worked; however one of my most favorite features is the coolpreviews. What is this all about?

THANKS I had it too with my macbook and never went on google Very disturbing Thanks again for the solution

To stop that annoying pacman sound just disable some of your add on like "cool previews". XD

To stop that pacman sound I just disabled "Cool previews" and voilá, the sound is gone....!!!!

The problem lies within the installation of CoolPreviews Add-On for Mozilla FireFox 3.6.3 and 3.6.2 version. Under Tools, Uninstall CoolPreviews to fix the problem

my bad... I had to disable all of the cool previews and then it worked

I had the same problem. I do have the add on Cool Preview and apparently the Pacman sound fx. is telling you that you need to update that add on. It worked for me after I installed the update to Cool Preview the Sound fx stopped ..Hope it works for you

Thanks guys, the disabling of CP has solved the problem for me. I hear that CP has an update, so once you upgrade your CP you can turn it back on if you like

Here's the solution I found

http://annoyances-resolved.blogspot.com/2010/05/google-pac-man-keeps-going-and-going.html