You appear to have a Firefox 115 version on Windows 7. If you are trying to install a current version like Firefox 137.0.2 or 128.9.0esr then they will not run on the eol Windows 7. Firefox 116.or later requires Windows 10, 11 to run. The most current Firefox 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