Microsoft allows you to install and use Windows indefinitely without a key. The only downsides are a watermark in the corner and no personalization options (wallpaper, colors). It is fully functional and legal.
This article is for educational and informational purposes only. The author and publisher do not condone software piracy or the use of illegal activators. Users are responsible for complying with all applicable software licensing laws.
: Some newer scripts attempt to inject "Digital Licenses" (HWID) to permanently activate Windows versions without needing a periodic server check-in. Critical Risks and Disadvantages
A background tool that automatically renews your activation every few months.