Sometimes when the browser thinks there is a problem with the profile, it will create a new one.

Look on your desktop. Do you see a folder called; Old Firefox? Look inside. Look for the folder with the latest creation date.

https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile

https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles

https://support.mozilla.org/en-US/kb/how-run-firefox-when-profile-missing-inaccessible

https://support.mozilla.org/en-US/kb/recover-user-data-missing-after-firefox-update

Note that the OP is on Windows XP. This platform is no longer supported with updates and 52.9.0 is the last version for this platform.

Users on Windows XP and Vista have been moved to the Firefox 52 ESR version.

• https://support.mozilla.org/en-US/kb/end-support-windows-xp-and-vista

See also:

• https://support.mozilla.org/en-US/kb/recover-lost-or-missing-bookmarks