Dear All, Could someone tell me how to judge user's OS is x86 or x64 through inf file? I would to make a 64bit ActiveX control installation, but I do not know how to judge the OS's version. The following is my code: [version] signature=$Chicago$ AdvancedINF=1.0 [DefaultInstall] CopyFiles=MyFiles RegisterOCXs=RegisterOCXSection [DestinationDirs] MyFiles=16422,NVR\Playback [MyFiles] Test.ocx=Test.ocx [Test.ocx] file=thiscab FileVersion=1,0,0,0 RegisterServer=yes [RegisterOCXSection] "%16422%\Test\Test.ocx" By the help of Google, I find the the website: https://social.msdn.microsoft.com/Forums/ie/fr-FR/32ec4e8f-cded-4f39-b57b-bea2222fdb92/how-to-create-x64-activex-controls-for-internet-explorer-64-on-vista7-64-editions-?forum=ieextensiondevelopment The web said I just need to set "file=thiscab" in the section, the 64bit could work. Could anyone tell me what's wrong? Thanks. Regards, Youlin