ReactOS is a free and open-source operating system for x86/x64 personal computers intended to be binary-compatible with computer programs and devices. Developed by Aleksey Bragin
License: Open Source
ReactOS aims to provide a free alternative to Windows and is designed to run Windows applications natively, while Lubuntu is a lightweight Linux distribution that focuses on speed and efficiency, especially on older hardware. ReactOS is still in alpha development, whereas Lubuntu is stable and widely used for general computing.