Your old Firefox profile may be corrupt. Fix: Create a new profile. Type about:profiles in the address bar → Create a New Profile → Launch fresh profile.
For these users, finding a compatible, safe, and functional web browser is a primary concern. While the latest versions of Chrome and Edge have long since dropped support for the OS, Mozilla Firefox remains one of the last bastions of modern browsing for Windows 7. However, there comes a point where even Firefox stops supporting older architectures. mozilla firefox download for windows 7 old version