Cloud programs do not use serial numbers... you log in to your paid Cloud account to download & install & activate... you MAY need to log out of the Cloud and restart your computer and log back in to the Cloud for things to work
Some general information for a Cloud subscription
Log out of your Cloud account... Restart your computer... Log in to your paid Cloud account
-Sign in help http://helpx.adobe.com/x-productkb/policy-pricing/account-password-sign-faq.html
http://www.adobe.com/products/creativecloud/faq.html
http://helpx.adobe.com/creative-cloud/help/install-apps.html to install or uninstall
http://forums.adobe.com/community/download_install_setup/creative_cloud_faq
What it is http://helpx.adobe.com/creative-cloud/help/creative-cloud-desktop.html
Cloud Getting Started https://helpx.adobe.com/creative-cloud.html