Depending on how you reinstalled Windows, your old data might have been saved. Can you find a folder with this name on your system?

C:\Windows.old\

To dig into that folder for your Firefox data, you will need to be able to view hidden folders. This Microsoft support article describes how to switch that setting: http://windows.microsoft.com/en-us/wi.../show-hidden-files.

Anything there like this:

C:\Windows.old\Users\username\AppData\Roaming\Mozilla\Firefox\Profiles

If you find the old profile file, this article may help in moving your saved passwords, but feel free to ask for assistance: Recover important data from an old profile.

See also:

• http://kb.mozillazine.org/Profile_folder_-_Firefox

• http://kb.mozillazine.org/Profile_backup
• https://support.mozilla.org/kb/Backing+up+your+information

thank you for your answer.i just formatted drive c and then changed my windows, i saw this: C:\Windows\Users\username\AppData\Roaming\Mozilla\Firefox\Profiles

but not in "windows.old", is it something to do?

That is the new profile folder that got created, so no old personal data in that location.

• C:\Windows\Users\username\AppData\Roaming\Mozilla\Firefox\Profiles

this link "http://kb.mozillazine.org/Profile_folder_-_Firefox" it makes me confused, i finde profiles in my computer, like that link say, but i dont know what to do. i just want my passwords back, please say it clearly, what should i do?

you mean i cant get to my passwords at all? oh god

You might be able to recover a signons.sqlite file via a low level search on the hard drive with a proper undelete utility as there is a very slight chance that these clusters haven't been reused, but it is likely impossible to recover the key3.db file with the encryption key as that is a binary file and you wouldn't know what to search for.

You would have to contact these websites and ask them to send a new password to the e-mail address used to create the account.

i found this "signons.sqlite", so what should i do now?

In the event that the passwords information is lost, you should record all information in a separate text file somewhere else on your hard drive. You can easily copy and paste if you need to do so. If you are concerned about someone else looking at that file, you can compress it using a password.

See also:

• Password Exporter: https://addons.mozilla.org/firefox/addon/password-exporter/
• Saved Password Editor: https://addons.mozilla.org/firefox/addon/saved-password-editor/