If you’ve copied the registry contents, make sure that you never start up the old server again. If you want to keep using it, there are some things that need to be done to it. (which I will detail later, if you require them)
For now, re-claim your new server. Start with this procedure: You need to reclaim your server, but don't dare to touch the Windows Registry
If you are running a Windows Server Edition, perform the actual claiming according to Plex install fix for Windows Server (Claim issue)
