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
Does your Cloud subscription show on your account page? https://www.adobe.com/account.html
Log out of your Cloud account... Restart your computer... Log in to your paid 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
-Install, update or UNinstall, and launch after installing
If you do not have a CLOUD program, what program do you have?