On my desktop running XP and my laptop running Vista the audible sound notification for Gmail has suddenly stopped working. I was using the extension Gmail Notifier I got as a Firefox add-on. I have uninstalled and reinstalled it; I have uninstalled it and installed Gmail Checker and Webmail Notifier. No luck with them either.

The .wav file is okay, ditto my speakers. I have also tried sounds from windows/Media. No luck there either. Any ideas? Thanks.