"You can't open Illustrator CS6 because it is not responding" after reinstalling Yosemite 10.10.5

Hey y'all!

I recently had to *reinstall* Yosemite 10.10.5 on my 2011 MacBook Pro (reinstalled as it was initially causing issue on my computer), the reinstallation fixed everything EXCEPT for when opening certain webpages (it would say I was using an unsupported browser or needed to update Java) and when trying to open Illustrator, I received a popup saying that I needed to install the legacy Java SE 6 runtime (I had Java 8 and had never encountered this problem before).

I found a thread on this same issue, with the advice to download Java for OS X at Download Java for OS X 2017-001

I did this, and this fixed the webpage issue (I can now view my gmail, yay!), but the Illustrator issue now reads "can't open illustrator CS6 because it is not responding"

Any insight or ideas on how to fix this?

(Apple suggested upgrading to El Capitan, but I'm apprehensive as I tried this last night and it almost killed my computer.)

Any help would be greatly appreciated! Thanks!