cschulkin said

I have downloaded different Firefox installer files. When I try to open any of them on my Windows 10 computer, they will not open or run. What else can I try?

Two questions :

1) Did you download Firefox (in your preferred language) from             here :

https://www.mozilla.org/firefox/all/  ?

2) In Windows Settings => Apps => did you choose "Allow all             apps"  ?

Yes, I did both of the things you suggested and I still cannot install Firefox.

Does it help to know that Microsoft Edge is installed on my computer, but is not working either. Only Google Chrome.

cschulkin said

Does it help to know that Microsoft Edge is installed on my computer, but is not working either. Only Google Chrome.

Did you install Google Chrome yourself  ? (just to make sure)

If Edge isn't working, that would be something to post on the official Microsoft support forum :

www.answers.microsoft.com/windows

Back to the problem of you not being able to install Firefox.

Do you have any security or anti-virus software installed  ? If so :   would you disable it and see if that wil make a difference   ?

If that's not it, would you please take a look at this article :

https://support.mozilla.org/en-US/kb/how-download-and-install-firefox-windows

Also see :

https://support.mozilla.org/en-US/kb/setting-firefox-default-browser-does-not-work

Scroll down to the section :

Note: If Firefox is not listed as a program choice

Thanks again for all your help. When I typed "disable norton" into Google, the firefox setup file executed and installed Firefox. However, now it is telling me "Your Firefox profile cannot be located." I looked for but cannot find profile.ini anywhere on my computer. Do you know how I can create one?

see this page:

• https://support.mozilla.org/en-US/kb/how-run-firefox-when-profile-missing-inaccessible