How activation works
Product activation reduces a form of software piracy that is known as "casual copying". Casual copying is the sharing and installation of software that is not in accordance with the software's end-use license agreement (EULA).
Product activation makes sure that each Windows XP license is installed in accordance with the EULA and is not installed on more than the number of computers that the license permits. Windows creates a unique installation identification (ID) that is based on information from the product ID and a hardware identifier that are created when you install Window XP. To activate, use the Windows Product Activation wizard to provide the installation ID to Microsoft over the Internet or your phone line. The installation ID records an association of the product ID to your computer and a confirmation ID is sent back to your computer to activate Windows XP.
Activation is anonymous, and no personal information is required to activate. The installation ID records an association of the product ID to your computer and a confirmation is sent back to Microsoft. You can then use the product key to install Windows on that computer an unlimited number of times. However, if you want to install Windows on a different computer with that product key, you may have to contact a Microsoft customer service representative.
Activation is required in 30 days from the first day that you start Windows XP. If you want to activate Windows on a day that is later than the day that you install it, a Windows Activation icon appears in the notification area. This icon periodically displays notifications to remind you about how much time remains before you must activate. After the 30 days has expired, you must activate Windows to continue using Windows.
During activation, you can also register your copy of Windows. Product activation is different from product registration because activation is required and registration is optional. If you want to register Windows XP by providing your name, e-mail address, and other contact information, you can also choose to receive information about product updates and other special offers.
Note Some original equipment manufacturer (OEM) and select installations of Windows XP that use a volume license agreement are pre-activated and require no additional steps to activate. To check your activation status, click Start, point to All Programs, point to Accessories, point to System Tools, and then click Activate Windows.