The phrase refers to methods, legitimate or illegitimate, used to enable a Windows operating system, specifically, possibly a high-definition version (“HD”), with a product key obtained through electronic correspondence. This might involve entering a purchased product key received via email, or, problematically, using illegally distributed keys found online. An example would be a user searching for a key after reinstalling Windows on a system and locating a key advertised online with contact information.
The importance stems from the necessity of operating system activation for continued functionality and access to updates. Without proper activation, Windows may operate with limited features or for a limited time. Historically, product keys were often physically delivered; however, electronic distribution via email became standard for digital purchases and electronic software distribution due to its efficiency and cost-effectiveness. Benefits of legitimate activation include full access to operating system features, security updates, and ongoing support from the software vendor.