In Windows XP (formerly code-named Whistler), Microsoft is instituting an antipiracy measure that will tie the product key to Microsoft Product Activation. The new measure will reduce casual copying by requiring users to register (aka activate) Windows XP over the Internet or by phone before using the product. Product Activation will create a unique identification code for each installation based on the product key and hardware-configuration criteria. If the user tries to install the same copy of Windows XP (i.e., software that has the same product key) on a different machine, the activation will fail. Product Activation is similar to the feature that Microsoft Office XP, which debuted this spring, uses. Windows XP is set to ship this fall.

"Consumers sometimes unwittingly violate their license agreement by sharing software with others," said Allen Nieman, the technical product manager for Microsoft's licensing technology group. "Through education efforts and the use of technology solutions like Product Activation, we're working to make sure that customers who choose Microsoft software products acquire genuine software and are eligible for technical support and product upgrades."

Microsoft says that Product Activation doesn't scan a user's hard disk or register the make and model of the PC with the company. Instead, the feature uses the product ID and hardware-configuration information to generate a random installation ID, which it then registers, along with the product ID, with Microsoft.

Users who are concerned that changing their system's configuration will affect the activation status of their Windows XP installation have nothing to fear: Microsoft understands that people upgrade components in their systems, and Product Activation accounts for this possibility. If a user completely recreates a system from scratch (e.g., simultaneously replaces the motherboard and other main components), the user must call Microsoft to activate the product when Windows XP's activation feature tries to reregister the OS upon reboot.

Microsoft designed Product Activation almost solely for individual licenses, so the feature won't affect most corporations, which typically purchase Microsoft products with volume licenses. Microsoft says that it will include Product Activation only in retail Windows XP versions or versions that consumers acquire through PC makers and other OEMs.