Wow all this time and you are getting somewhere now.
If you have a very early version of firefox (you never said what it is), then the update was worse than useless (as Frank said), even Mozilla didn't recommend using it, rather download the latest version, uninstall, boot and install the latest version. From firefox 1.0.2 it has improved slightly, enough so to have Mozilla ask people to use it (and report if they have problems
). But the safest option is to download new, uninstall, boot, install new.
Try what 'radicalb21' has said and let us know how you get on.