I just finished my free trial for Adobe Creative Cloud. I was using Illustrator, InDesign, Bridge, Lightroom, Photoshop and more. Now, when I try to join, it asks me for my serial number. I don't have a serial number, so it asks me for my registration, which doesn't seem to exist. I have been running through all of the Adobe pages trying to find a way to simply get a years subscription to Creative Cloud, but I can't find a way.
Some general information
Log out of your Cloud account... Restart your computer... Log in to your Cloud account
http://helpx.adobe.com/creative-cloud/help/install-apps.html to install or uninstall
Cloud Getting Started https://helpx.adobe.com/creative-cloud.html