Are you the only user of this computer? It sounds highly bizarre that something would trigger Firefox to install an old version on top of a newer one -- Firefox itself would certainly never do that.

Could it be that you have two, somehow concurrent installations on the computer, and that the shortcut you're using to launch Firefox somehow points to the old version? One way to find out would be to manually go into the Program Files folder and check if you indeed have two folders with the name "MOzilla Firefox", "Mozilla", "Firefox" or similar.

You may have security software that has a virtualization or sandbox feature that restores files automatically or a reboot.
You can check if you can disable such a feature or ask advice on the support forum of that software.

Do a clean (re)install and delete the Firefox program folder (C:\Program Files\Mozilla Firefox\).

Download a fresh Firefox copy and save the file to the desktop.

• Firefox 9.0.x: http://www.mozilla.org/en-US/firefox/all.html

Uninstall your current Firefox version, if possible.

• Do NOT remove personal data when you uninstall the current version or you lose your bookmarks and other data in the profile folder.

Remove the Firefox program folder before installing that newly downloaded copy of the Firefox installer.

• It is important to delete the Firefox program folder to remove all the files and make sure that there are no problems with files that were leftover after uninstalling.
• http://kb.mozillazine.org/Uninstalling_Firefox

Your bookmarks and other profile data are stored elsewhere in the Firefox Profile Folder and won't be affected by a reinstall, but make sure that you do not select to remove personal data if you uninstall Firefox.

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

• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Clean_reinstall

Ok I did exactly what you told me, thank-you very much.. I'll give it a few days and see if that worked. again thank-you

there was not more than 1 firefox folder and it is just me and my husband using the computer. I do all the updating and cleaning of the computer, I am going to try what cor-el suggested...thank you so much for your imput. I would have never thought to look for a second folder.

well it was going good for a while until there was another firefox update and it is doing it all over again.....I wish that Mozilla had someone to call and talk to them to help me out...