bogus message states "you are running an operating system that Adobe no longer supports" I'm trying to download a free trial of ai creative cloud.

My iMac hardrive crapped out. I've installed a new 2 TB hardrive & I'm reloading my Illust.CS3 software. Messages indicate my licencing expired and I've gone through all the suggested Adobe fixes and still fail the installation. Any Suggestions?

Now I'm trying to download a free trial of Creative Cloud and computer message states that i'm running an operating system Illustrator no longer supports???