Changes in Windows XP Product Activation
On February 28, Microsoft will disable Internet activation for all Microsoft Windows XP product keys located on the Certificates of Authenticity (COA) labels distributed by large, multinational OEMs.

Direct OEMs of Microsoft (large multinational OEMs that that have a direct signed license agreement with Microsoft) usually preinstall Windows software using System Lock Preinstall (SLP), which is a direct OEM’s method of legitimately bypassing Product Activation on behalf of their customers.

Read the complete story . (Aviran’s Place)