Uninstalling the uninstallable -- old, dead Java Consoles in Firefox
There they are, every time. You say no to the Yahoo! toolbar, but each time you update your Java runtine, your extensions list accumulates another disabled Java Console 6.0.xx that won't uninstall through Firefox.
To get rid of an old 6.0.xx extension, go to C:\Program Files\Mozilla Firefox\extensions
and just delete the folder called {CAFEEFAC-0016-0000-00xx-ABCDEFFEDCBA}
, and you're sorted.
You can use the same trick to get rid of other extensions that won't take a hint (e.g. the Skype extension). The folder is another {Guid}
-- look in the chrome.manifest file inside the folder for one containing appropriate names; or check the date of the folder against the date you last installed/updated.