Here's the process to roll back. You also will want to change your automatic update setting under Tools > Options > Advanced > Update after reinstalling.

First, I recommend backing up your Firefox settings in case something goes wrong. See Backing up your information. (You can copy your entire Firefox profile folder somewhere outside of the Mozilla folder.)

Next, download and save Firefox 3.6 to your desktop for future installation. http://www.mozilla.com/firefox/all-older

Close Firefox 5.

You could install Firefox 3.6 over it (many have reported success) or you could uninstall Firefox first. If you uninstall, do not remove your personal data and settings, just the program.

Unless you have installed an incompatible add-on, Firefox 3.6 should pick up where you left off. If there are serious issues, please post back with details.

Thanks for that jscher.

I'm now back at 3.6.18. The only snag was that I updated FireFTP under FF5, but I've reinstalled that and all is well.

Thanks again

Tony