A "free" key found on a forum is almost certainly illegal or malicious. For the safety of your data and the stability of your machine, it is highly recommended to transition to a modern, supported Linux distribution or explore official lightweight versions of modern Windows.
Using a key you did not purchase technically violates Microsoft’s End User License Agreement (EULA) . Common Windows 7 Generic Keys windows 7 super lite product key free
Windows 7 "Super Lite" is an unofficial, third-party modification of Windows 7 that removes core system components to reduce hardware requirements, often fitting into an ISO as small as 650MB to 800MB Important Safety & Legal Warning A "free" key found on a forum is
Since Windows 7 reached its End of Life in January 2020, it no longer receives security updates. This makes it highly vulnerable to modern exploits. If you have an old PC, consider these more secure, lightweight alternatives: Common Windows 7 Generic Keys Windows 7 "Super