You appear to have posted with a Firefox 115 version on Windows 7. Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:109.0) Gecko/20100101 Firefox/115.0

Firefox 116.0 and later requires Windows 10, 11 to run.

The most current version you can run on Windows 7, 8, 8.1 is Firefox 115 ESR currently at 115.22.0esr and will be updated til 115.27.0esr in August unless Mozilla extends updates again. https://support.mozilla.org/en-US/kb/firefox-users-windows-7-8-and-81-moving-extended-support

please reply in common english. I DON'T have a degree in computers

You say you want to update Firefox, I mentioned that since you appear to be using Window 7 the most current version you can run is Firefox 115 ESR currently at 115.22.0esr.

You cannot install and use the current Firefox 137.0.1 Release and 128.9.0esr version on the old Windows 7.

The KB article I linked to has more information.