Key features of the Windows operating system include a user-friendly graphical user interface (GUI), multitasking capability, and extensive software compatibility. Windows supports a wide range of applications, from productivity tools to gaming, making it versatile for various user needs. Additionally, it incorporates built-in security features like Windows Defender and regular updates to enhance user protection. The operating system also facilitates network connectivity, allowing easy integration with local and internet resources while providing support for peripherals and various file systems.