This is not an issue that Firefox itself is going to cause. Maybe it is your backup software or something.

Firefox has no mechanism for causing reverts to older installs. When Firefox does upgrade it does try to preserve bookmarks. I note from your Sytem information aside that you have McAfee software, but I do not know whether that may be implicated in this sort of problem.

I do know; certainly in the past; some McAfee software, and particularly the SiteAdvisor have caused Firefox problems.

N.B. Firefox has its own built in features

• How does built-in Phishing and Malware Protection work?
• And Windows provides basic AV software for free http://windows.microsoft.com/en-gb/windows/security-essentials-download

I could try to give some basic help information regarding Windows features for recovering previous versions of files

• - Please - always carefully back up any existing files or folders before attempting that
• http://windows.microsoft.com/en-us/windows/previous-versions-files-faq#1TC=windows-7

I suspect however your problem may relate to use of third party backup or security software.

• What security related software and backup software is in use ?

Which security software (firewall, anti-virus) do you have?

Is there really an older Firefox version shown in "Help > About" or did you only lose personal data (settings)?

Problems with bookmarks and history not working properly can be caused by a corrupted places.sqlite database file.

You can check for problems with the places.sqlite database file in the Firefox profile folder.

• http://kb.mozillazine.org/Bookmarks_history_and_toolbar_buttons_not_working_-_Firefox
• https://support.mozilla.org/kb/Bookmarks+not+saved#w_fix-the-bookmarks-file

See also:

• http://kb.mozillazine.org/Preferences_not_saved
• http://kb.mozillazine.org/Multiple_profile_files_created