Run ReSharper Ultimate installer and click on "Options" button:
In some corporate environments, installations of programs into user profiles are not allowed. In this case, you can install desired JetBrains .NET tool into the 'Program Files' folder and thus make them available for all users on the current machine. This installation mode is not compatible with existing installations in user profiles. That is, if there are any JetBrains .NET tools installed in user profiles, you need to uninstall them before installing into 'Program Files' and vice versa.
To generate a Command Line to install the products this way via CMD, tick "Administrative mode" checkbox as well.
For more information about Machine-Wide install, please refer to this Web Help article.