You will need to execute some commands in order to make Security Center detect installed antivirus solutions.
Please open a Command Prompt (Start > Run > cmd) and type: net stop winmgmt and net stop wscsvc then proceed and delete the following directory: %systemroot%\system32\wbem\Repository where %systemroot% is usually C:\ drive. After you delete the folder, restart the computer and start the services again and the Security Center will successfully detect installed antivirus.