Please define what you mean when you say “Plex installation”.
Are you referring to the Plex program files and executables? These should always be located at their default location under C:\Program Files (x86)\Plex\Plex Media Server
This can be changed by uninstalling Plex server (using the dewfault Windows ‘Apps’ control panel), followed by a fresh installation with location set to default.
This folder doesn’t hold any information about you, nor your media collection.
Or are you referring to the Plex data folder?
If the location of this has changed, you need to tell Plex server by changing a key in the Windows registry: [HowTo] An extended guide on how to move the Plex data folder on Windows
