Hi I'm creating an installable for which I need to know version of Operating System where setup will be installed. I tried to use many API's like VersionNT, SYSINFO.nWinMajor, SYSINFO.nWinMinor, GetSystemInfo. But still I'm not getting correct OS version. If I use following code, then I get error, VersionNT, undefined identifier. ex. if (VersionNT == 601) then MessageBox("Windows 7 OS", INFORMATION) else MessageBox("Not Windows 7 OS", INFORMATION) endif; If I use SYSINFO.nWinMajor, SYSINFO.nWinMinor then I get minor version as 0. So eventhough my OS is win 7, it displays message box "Not Windows 7 OS". Let me know what's solution for this? ... View more