When installing your OLE application, you must copy OLECLI.DLL and OLESVR.DLL to the SYSTEM subdirectory of the user's Windows directory (the directory in which Microsoft Windows is installed; the GetSystemDirectory function in KERNEL.DLL returns the path of the system directory). For example, if Microsoft Windows is installed in a directory called \WINDOWS, then you must copy OLECLI.DLL and OLESVR.DLL to the \WINDOWS\SYSTEM directory of the user's hard disk.
Both files need to be copied, regardless of whether or not the application being installed needs both of them. This procedure safeguards against there being different versions of the DLLs on the same workstation.
The setup program should check the user's SYSTEM subdirectory to verify that copies of the files are present. If the files are already present, the version information should be checked to make sure that newer versions will not be overwritten by older versions.