Thank you for posting to this public discussion forum, @sinkii.
I appreciate your continued use of our software and services, and I apologize for any confusion you may have encountered while installing and activating your Creative Suite 5.5 Design Standard license.
I checked your account, and the copy you registered in 2013 is a volume-licensed copy of Creative Suite 5.5 Design Premium for Windows, @sinkii.
Activation is not a factor for most volume license installations, but you will need the correct installation files to complete the installation and licensing process. The installation files available under your account on Adobe.com are retail license files, not volume license files that are required to use your serial number.
Please see https://helpx.adobe.com/x-productkb/policy-pricing/volume-licensing-site.html for information on how to access the installation files that were provided with your organization's purchase of Creative Suite 5.5.
Please update this discussion thread if you have any additional questions, @sinkii.