Unable to install new version of Illustrator AND keep current version.

 I previously had the two versions running on this PC, but had some hardware issues and the repair ended up in a clean install of Windows which means re-installing CC and apps. I have Creative Cloud preferences set to Auto Update and "Remove Older Version" is unchecked and "Show Older Apps" is checked . But when I attempt to manually install the newer Illustrator it removes the current. I need to keep the old version for compatibility issues with some of my plug-ins and access to the Pantone color book. How can I prevent CC from uninstalling my current AI version?