http://support.mozilla.com/en-US/kb/Installing+a+previous+version+of+Firefox

In the add/remove programs dialogue you should have firefox 4 beta and firefox 3.6.x listed. Just uninsall the beta and everything will spring back to life.

This just worked for me on Vista.

Thanks so much. The solution was sooo easy but I had to search and search and then ask a question just for something that should have been explained on the update page. Words like "if you don't like this version, simply uninstall and the old version will return!"

I really appreciate the fast response! Thanks again!

Firefox 4.0 Beta(s) & Firefox 3.6.* are not intalled in the same directory. its like you are installing 2 version of Firefox in your system. :D

Look the Desktop Shortcut Name

The 3.6.* desktop name is Mozilla Firefox

And the 4.0b1 desktop name is Mozilla Firefox Beta1 or 2 etc...

So you can uninstall 1 or both programs... :P

What is the best way to handle this? I do not like Beta 4.

Version 4.0 Beta is best for a user using Win Vista, Win 7 & of course the Beta Testers :D

I advice to you to stay in current stable version 3.6.* You can upgrade to 4.0 when the RC is out :P

Thanks, I just uninstalled Beta 4.0 and 3.6 is working just fine.

I have the same problem but when I try to uninstall 4.0 it comes back with an error saying "ERROR LAUNCHING INSTALLER" and goes back to my desktop.. I can still use 3.6.6 just fine except for a few unusable things from previous version but all and all it works just fine. I just want to delete 4.0 off my system until a more stable version is available...

Go here and you can download previous versions of Firefox, uninstall FF4 and install which ever of these you want, http://www.oldapps.com/firefox.php?old_firefox=113