thanks very much for the solution

I uninstalled "CoolPreview" add-on and restarted Firefox, solved the problem.

Thank you so much. Disabling cool previews worked for me too. why does it work? What was going on here?

Jesus Christ, thank you very much!!!

I also disabled "Cool Preview" and the siren fianlly stopped. This works. Thanks Anoniem.

Thanks !!! Muito Obrigado.... Problema resolvido.

I don't have cool previews installed. I put my sound on mute as a temporary solution. I was fine this morning, but this afternoon (just now - 4pmish in the east) it happened. I'm running windows xp 2002.

Any suggestions?

remove me from this subject please

Unfortunately disableing COOLPREVIEW or COOLIRIS does NOT stop the horrible sound on my Mac !!! Anyone has a solution of a Mac ? Thanks in advance, Franck

I have the same problem as of a half-hour ago. I recorded the sound on my iPhone, then I called Apple: 1-800-MY-APPLE. The tech says it's not a sound programmed into their computers, so there's nothing they can do.

The Apple tech suggested clicking Apple icon in upper left, choosing "Force Quit" from pull-down menu, and seeing what's open. I forced Firefox to quit, and the sound stopped...for now.

I've never had this experience before, but apparently I'm not alone. Someone in another forum suggested that this sometimes happens when the CPU (Central Processing Unit) overheats.

I just learned the MacBook Pro, which I have, has a reputation for running hot. (Too hot to sit on my lap sometimes, which is sorta-kinda the point of having a "laptop," duh.)

I have a hunch that, in my case, the CPU is wailing for a cool down. I've been running the machine on a flat desk, whereas I generally have it propped up on an iCare stand, which allows for aeration.

We shall see. So far, so good; no siren. But it's the freakiest thing I've ever encountered with this machine. And given the formidable cohort of complainants on this annoying issue, I'm surprised that Apple is shrugging its shoulders and scratching its head.

Thank's for te solution, it drives me CRAZY!!!

Post script to my previous message... My attempt to stop the annoying siren by cooling my laptop jets didn't work. The sound is back with Firefox. Disabling Cooliris Previews also didn't work. This is horrible!!!

thanks for the tip guys. what the heck is wrong with cool previews.

Estava com o mesmo problema hoje e desinstalei o cool preview e ficou tudo bem, sem barulho.

I have updated CoolPreviews to the newest version (3.1.0521) and the siren stopped. Seems to be an annoying reminder of upgrade.

As instructed, I disabled Cook Previews and the problem is solved!

It's caused by googles Pacman theme: http://support.mozilla.com/en-US/forum/1/677839

which you can play on: http://www.google.com/

Just install the newest version of Cool Previews. They had a line of old code that would load up the Google homepage in the background. You can find it on coolpreviews.com. Should solve the problem.