You have a pull-down menu on the left-hand side of the search bar . Click on the little down-arrow there to open it and select Manage earch engines... to reorder them.

If you have problems with setting the search bar to Google then try these:

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the extensions or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox (Tools) > Add-ons > Appearance/Themes).

• Don't make any changes on the Safe mode start window.
• https://support.mozilla.com/kb/Safe+Mode

See also:

• http://kb.mozillazine.org/Unable_to_search_or_add_new_engines

Thank you for helping me. I found the pulldown of the search engine block and selected Google. It has stayed on Google since then which is a comfort. Thank you for the advice. I was beginning to give up.