I solved this, but cannot delete the original question. Sorry for taking up the bandwidth.

Don't worry about that. But please post your solution so that others will know what to do.

Here are some free gifts;

Context Search {web link} Expands the context menu's 'Search for' item into a list of installed search engines, allowing you to choose the engine you want to use for each search.

Bookmark and use this; Mozilla Search Reset {web link} This add-on is very simple: on installation, it backs up and then resets your search preferences and home page to their default values, and then uninstalls itself. This affects the search bar, URL bar searches, and the home page.

Settings Guard for Firefox {web link} Detects and resets changes to settings that are frequently done by add-ons and application installers.

SearchThisSite {web link} Allows you to search the website currently viewed with the website's internal search engine (and not the default FF search engine or an external engine)

You are right. I should have done that.

I simply clicked on the small down arrow in the search bar, selected "change search settings", then selected "restore default search engines" in the window that opened. Bing was one of the "default search engines" in the list. Then I just deleted the ones that I did not want.

Apparently, when you delete from this menu, FF keeps a record of them anyway. They are not really "deleted". So, if you subsequently try to add one that was on the list, FF will give an error message saying it is already loaded. The problem with that functionality is that, even if it is "loaded", it is not visible if you have previously removed it from the list. There does not seem to be any way to add just one of these "deleted" search engines once you have deleted it. You have to add the whole list back, then again remove the one(s) you don't want. It's cludgy, but it works.

PS: Tks for the links.