1. Enter this link: https://support.microsoft.com/en-us/help/2977003/the-latest-supported-visual-c-downloads
2. From the Visual Studio 2015, 2017, 2019, and 2022 section, download the following executable file: vc_redist.x64.exe
3. Install this file
4. Restart the computer and run Firefox

Hi Mom, if you run Webroot security software, here is information on an incompatibility:

A recent Windows 10/11 update plus Webroot plus 64-bit Firefox 97 can mostly disable Firefox.

Webroot is working on an update, and the next release of Firefox probably will also have a workaround.

Until then, a couple users confirmed that uninstalling and reinstalling Webroot resolved the issue.

If you can't do that or it doesn't work, several other users confirmed that one temporary workaround is to run Firefox 97 in backwards compatibility mode. Here is how you would set that up:

(1) Open the Properties dialog for your Firefox shortcut. Either:

• right-click a Desktop shortcut, then click Properties
• right-click a pinned Taskbar icon, then right-click the Firefox (or Mozilla Firefox) item, then click Properties

(2) Switch to the Compatibility tab

(3) Check the box for "Run this program in compatibility mode for"

(4) If the selector for that option is not set on Windows 8, switch it to Windows 8

(5) Click OK and then start Firefox (if Firefox won't start because it is already running, you might need to restart Windows)

As a result of this change, you may notice that some Windows 10-specific features and styling are disabled. However, I am not aware of any major changes. If you experiment with this, let us know your experience.

In case you do have Webroot.

https://www.mozilla.org/firefox/97.0.1/releasenotes/

Fixed Works around problems with WebRoot SecureAnywhere antivirus rendering Firefox unusable in some situations