Hello James! Have you tried running a quick, full, custom or Microsoft Defender Offline scan?

First, do a reboot of the computer. Any help?

Start Firefox using Troubleshoot(Safe) Mode {web link}

A small dialog should appear. Click Start In Troubleshoot(Safe) Mode (not Refresh). Is the problem still there?

Thanks but the problem is still there.

I did run the Windows Defender full scan, some corrupt files found and repaired. Firefox still not working. Everything else seems to be working.

Some problems occur when your Internet security program was set to trust the previous version of Firefox, but no longer recognizes your updated version as trusted. Now how to fix the problem: To allow Firefox to connect to the Internet again;

• Make sure your Internet security software is up-to-date (i.e. you are running the latest version).
• Remove Firefox from your program's list of trusted or recognized programs. For detailed instructions, see

Configure firewalls so that Firefox can access the Internet. {web link}

Thanks, Fred. I was able to use the links to configure my Windows firewall. I removed Firefox from the allowed list, rebooted and then added it back. Nothing changed. Firefox appears to open but just sits there.

You can check for issues caused by a corrupted or incomplete Visual C++ installation that is missing runtime components (Redistributable Packages) required by Firefox, especially VCRUNTIME140_1.dll.

See "Visual Studio 2015, 2017 and 2019":

• https://support.microsoft.com/en-us/help/2977003/the-latest-supported-visual-c-downloads

• https://aka.ms/vs/16/release/vc_redist.x64.exe
• https://aka.ms/vs/16/release/vc_redist.x86.exe

You may not need the latter (32-bit version) if you use 64-bit Firefox. You may have to reboot the computer.

Thank you, cor-el, that did it. I would never have thought of that. May you continue to have and share many blessings. Yay, Firefox rides again.