Windows 2000, XP, Server 2003, Vista, and Windows 7 (32-bit only supported). Mac: Mac OS X 10.5 (Leopard) or 10.6 (Snow Leopard). Hardware: A Pentium 4 or newer processor with SSE2 support. Critical Security & Usage Warnings
Firefox 7.0 contains hundreds of known, unpatched security holes that can lead to malware infections simply by visiting a compromised site. mozilla firefox old version 7.0 download
Mozilla maintains an official archive of all past releases. You should download old versions from Mozilla’s Official FTP Server to ensure the installer hasn't been tampered with by third parties. Download Link (Direct Archive) Windows Download Windows 32-bit (x86) macOS Download Mac OS X (10.5+) Linux Download Linux i686/x86_64 Key Features of Version 7.0 Windows 2000, XP, Server 2003, Vista, and Windows
The http:// prefix was hidden in the address bar for the first time to simplify the URL view. Critical Security & Usage Warnings Firefox 7
Enhanced rendering for HTML5 Canvas and improved startup times.
If you need an "old-school" feel with modern security, consider the Firefox Extended Support Release (ESR) or lightweight forks like Pale Moon that maintain compatibility with older web standards. Firefox 7.0 System Requirements