Still being asked for serial # and other errors

I've been using Illustrator and Photoshop that were purchased and installed before I subsrcibed to Creative Cloud. Both started giving me error messages and telling me to re-install. I tried downloading them, got several errors. Finally Illustrator downloaded and installed but then asked me for my serial number rather than my Creative Cloud subscription info. Shouldn't I be getting them as Creative Cloud applications with updates rather than serial-number based purchases? How do I get my previous software into the Creative Cloud system? (By the way, it took three separate downloads just to get the installer to work...) I'm worried my whole Creative Suite system is screwed up. Help needed!