Where did you find the backup of your bookmarks? If you have a backup of your entire profile folder, there are a pair of files in there you can copy over to your currently live profile folder to transfer your saved login. More info on the various files in this article: Recovering important data from an old profile.

Thank you! By your naming those exact pref files, I was able to find them in the BackUp and drag them to replace the ones in the new copy of Firefox. WooHoo! Saved years of logins.

These add-ons can be a great help by backing up and restoring Firefox

FEBE (Firefox Environment Backup Extension) {web link} FEBE allows you to quickly and easily backup your Firefox extensions, history, passwords, and more. In fact, it goes beyond just backing up -- It will actually rebuild your saved files individually into installable .xpi files. It will also make backups of files that you choose.

OPIE {web link} Import/Export extension preferences