You can uninstall the Firefox and then install the version you want.

If you want an older version and don't have the installation file you can download all of the releases of Firefox here:

Firefox All Releases

IMPORTANT NOTE: Don't forget that the previous versions might have security problems. For the latest security updates you MUST upgrade to latest version. That's what I STRONGLY recommend. Thanks!

So I have to completely uninstall the current version? Won't I then lose all the information stored in the browser, like bookmarks? Is there no way to just uninstall the upgrade?

Well it is not like you're upgrading! You're downgrading your browser!!!

But don't worry, downgrading process is just like upgrading. So you can install an older version without uninstalling of Firefox!

Don't forget to hit 'Solved it'.

IMPORTANT NOTE: Don't forget that the previous versions might have security problems. For the latest security updates you MUST upgrade to latest version. That's what I STRONGLY recommend. Thanks!

Will downgrading from ff 6 then let me read my verizon email? Now I have to use Outlook.

I don't know about that, however it's really not recommended to use the previous versions. So please take a look at this IMPORTANT NOTE:

IMPORTANT NOTE: Don't forget that the previous versions might have security problems. For the latest security updates you MUST upgrade to latest version. That's what I STRONGLY recommend. If you really want to downgrade the recommended version is 3.6.21. Thank you for paying attention!

CseC posted a link to "Firefox All Releases"... I get a 404. page not found.

I also want to roll back to a working version.

I 'upgraded' to 6.0.1 and now when I visit web sites Firefox does not mark about 30% of the pages as having been Read.

It also keeps trying to shove Google Chrome and Google toolbars at me,l which I do not appreciate.

to tomreilley : ftp://ftp.mozilla.org/pub/mozilla.org/firefox/releases/

The link has no problem. (All found my posts unhelpful?!) I just clicked on it my self! The link is working. The same as the one ideato came up with.

Only because I fixed it as you have been linking to it as http://ftp://ftp.mozilla.org which would lead to http://rumba.microfocus.com/

@ James Oh, sorry. I didn't know that. I had that link in some other topic posted, I never thought I might post it with an error here. Thanks for the support.

I guess I'll have to re-download Firefox so I can get the version that I like which DOES NOT SLOW THE SYSTEM DOWN TO A CREEPY CRAWL LIKE VERSION 6.02 IS DOING RIGHT NOW....WON'T TOLERATE THIS AT ALL...INTERNET EXPLORER'S SEEMS TO BE FASTER NOW. I'D USE CHROME, BUT U HAVE TO TYPE EVERYTHING IN. I'VE USED FIREFOX FOR, SEEMS LIKE FOREVER, AND NOW IT'S LIKE IT HAS A ANTIVIRUS ATTACHED TO IT, I.E. MCAFEE OR AVG...THEY SLOW MY INTERNET CONNECTION WAAAAAAAAAAAAAAY DOWN...THANK YOU FOR NOTHING.