I checked my build number in the registry today and found it listed as this: 7600.16617.x86fre.win7_gdr.100618-1621 I found this under: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion I installed Windows 7 Ultimate from: 7600.16385.090713-1255_x86fre_client_en-us_Retail_Ultimate-GRMCULFRER_EN_DVD.iso I have not installed any service packs, how can my build number be newer??