Your personal data from Firefox is not stored in the Firefox program folder, but is stored in the Firefox profile folder that is located in the AppData\Roaming\ folder.

• C:\Users\<user>\AppData\Roaming\Mozilla\Firefox\Profiles\<profile>\

You can use this button to go to the current Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder)
• http://kb.mozillazine.org/Profile_folder_-_Firefox

If you didn't backup this profile folder then your bookmarks and other personal data is lost.

See also:

• https://support.mozilla.org/kb/restore-bookmarks-from-backup-or-move-them
• http://kb.mozillazine.org/Backing_up_and_restoring_bookmarks_-_Firefox

Common mistake majority of programs save user data elsewhere on pc and I find it comical people think they can copy the programs folder and toss it back on new computer and programs and their settings will load just fine. That is not the case. When you load many programs it loads them taking note of the hardware too.

C:\Users\(User's computer name)\AppData\Roaming\Mozilla\Firefox\Profiles\ (b8rn67da.default-1322828212300) < Ending Profile number/name varies

Or you can go to top of Firefox Menu Bar >Help then go to > Troubleshoot Information on the top Left under Application Basics click the button called Show Folder that will open you user folder for Firefox that shows you personal saved info like saved bookmarks.

So if you just saved the only Programs folder, you lost your bookmarks.

Depending on how you reinstalled Windows, you may find a folder named

C:\Windows.old

which contains your earlier settings. By any chance do you have that?

i guess i lost them then. no "windows.old", lol.

i find it comical that the hyper intelligent elves that make computer software cant figure out how to make it simple enough for morons like me to use.  why not also store a copy of your settings and bookmarks in the firefox folder?  no built-in redundancy for dolts like me?  

most people are busy working and dont have time to learn about software or coding. instead they build houses and cars, farm food, practice law or medicine, etc.

internet is a scam

You can have more than one Windows accounts on a computer and you do not want other users to have read/write access to your personal data. The Firefox program folder would the common for all users and would also require Administrator permission to have write permission, so that isn't an option. personal data from a specific user should always be stored in the user account of a user and never in a location that all users can access.