KB971033
From Free Knowledge Base- The DUCK Project: information for everyone
Checks to verify if the Windows 7 installation is legitimate or pirated.
It's called "Update for Windows 7 for x64-based systems (KB971033)". The description says: "This update to Windows Activation Technologies detects activation exploits and tampering to key Windows system files. These exploits try to bypass regular Windows activation and are sometimes included within counterfeit copies of Windows."