You can prepare for a smoother transition, by moving your Plex data folder to a separate drive. (Preferably an SSD)
Follow these instructions: Moving Metadata on Windows
Then you save the Plex branch of the Windows Registry, as described in the link you have cited above.
Note down all the drive letters you have currently assigned to your media drives. Make sure to identify each drive, so that you can assign each drive the exact same drive letters under the new Windows.
(Instructions how to do that in the below link)
Once the new Windows is installed, double-click the exported registry branch. From then on, it should all work as before.
If you failed to note down the drive letters or missed exporting the registry settings, follow this procedure instead: My computer went kaput...now what?
