Firefox being detected as IE6?

[Kee123]

For some reason, my Firefox is now being detected as Internet Explorer 6

I only noticed because Facebook alterted me that I might want to upgrade to IE7 or Firefox. So I checked on one of those forum signatures that detect IP, OS, Browser etc. And it said WinXp, IE6. Pretty messed up.
Also, when I go on Gmail, it's now set to the HTML version, so I assume this is because it sees my browser as IE6 too.

I've tried reinstalling Firefox, no luck. But that was just a simple trash can uninstallation, as I noticed that all my bookmarks, settings, extensions were still there, fortunately.

I believe it may be caused by a Megaupload extension I foolishly installed, from a Spanish Wii Forum (I don't even speak Spanish) - https://addons.mozilla.org/en-US/firefox/addon/3843
Although, I've removed the extension now.

Any ideas?

Edit - I'm running Leopard.

 

[clevin]

1. try UA switcher https://addons.mozilla.org/en-US/firefox/addon/59
a typical UA for Mac Firefox is

Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en-US; rv:1.8.1.10) Gecko/20071115 Firefox/2.0.0.10

2. if you goto about:config page of your firefox, is there an entry called general.useragent.override ?

3. Eventually, if you want a brand new start, just create a new profile. (copy out your bookmark and passwords first, extensions and themes will be lost)