I'm not sure which version of Firefox I had when this problem started, which was probably in early June, or even May.
I have WebMail Notifier 1.0.10, which I had my Gmail, Hotmail and Yahoo email addresses in it, worked fine, then the Yahoo address kept asking for security type this mess of numbers and letters that are almost unreadable, and when you do, it asks again about 5 minutes later. This kept happening so I deleted Yahoo from the email notifier, problem solved, right........... of course not.
Shortly before I went away the notifier wasn't checking the Gmail address, and when I first turned on the computer last night when I got back, it wasn't checking any of them.
Firefox did let me know a new update was ready, and when I tried to install it, it failed, error code 203, or similar.
I tried finding updates for all add-ons, any add-on updates will be installed when Firefox is restarted, nope! So I tried uninstalling Webmail Notifier, will be uninstalled when Firefox restarts, nope.
Installed 2.0.0.16, nothing changed. Installed 3.01, doesn't have an email notifier and other add-ons I tried to install wouldn't except the Aussie Dictionary, figured I needed it. Not really necessary as I know all Aussie swear words, and up until this point I've used most of them.
I decided to go back a few versions, 2.0.0.13, add-ons still the same, and according to Add/Remove Programs I have Firefox 2.0.0.16 and 3.01.
IE is looking good at this stage.