You may be referring Bing as to the Windows default browser which is Microsoft Edge and its default search engine is Bing. Windows gives all of us a difficult time when trying to set your default browser and getting rid of Edge.

I am not a Windows user but I have someone who uses it and have solved this issue before. Here's a YouTube video to help with this issue. https://www.youtube.com/watch?v=1rVmAtb-FA0

The video shows you how to do it in Windows 11. If you have Windows 10 and not 11, they both are practically the same so no need to worry.

Hopefully this helps!

Thank you for your reply. Unfortunately when I did EXACTLY as instructed in the video, nothing changed. When I log onto the internet, the Firefox window opens, but the Bing (or Edge) window immediately opens on top of it. But I appreciate your trying to help.

At this point you need to go online and search how to remove Bing from Firefox and read the search results on how to do this if that is the problem. There is no firefox link but other links talking about this and how to do it.