EX PEE will not be cracked!!! Windows XP SP1 Will Not Install on Known Pirated Installations. In an email sent to OEM system builders MS tells: When released, Service Pack 1 for Microsoft Windows XP will not install if it identifies the underlying Windows XP installation as a known pirated installation. SP1 identifies known pirated installations by their Product IDs. The Product ID is generated from the Product Key used during install and can be found by choosing My Computer, then Properties, and viewing the General tab. Press Read More for further info!!

SP1 will not install on installations with the following product IDs containing the following serial numbers (note that X takes the place of any other value): XXXXX-640-0000356-23XXX, & XXXXX-640-2001765-23XXX. Users of licensed Microsoft software will be unaffected. If SP1 is installed on a Windows XP installation with one of the above product IDs, SP1 installation will fail and error with the following message: Service Pack 1 Setup Error: The product key used to install Windows is invalid. News Source: Neowin
Further Info: Windows XP Service Pack 1 News Thanks Voodoo of Neowin for this story ;-)