May I see a screenshot for a laugh please? hehe
Anyway, where did you download Firefox? I'd reccomend downloading it directly from http://mozilla.org
I don't know where it is exactly, but you might be able to manipulate the version number that appears somewhere in the Registry. (Start>Run>Regedit)
To fix it, I'd remove Firefox completely (including the directory), and do a clean install.
That will fix it, I'm sure.