Regardless of where Orbx products or addon aircraft are installed, the P3D installer will leave them alone because it can only uninstall files that it installed in the first place.
1. Using the Windows control panel, uninstall the P3D v5 client, and when asked if you want to deactivate P3D v5, answer No.
2. Then uninstall the content and then the scenery and finally the top P3D v5 entry in the Windows control panel.**
3. You will now be left with a P3D v5 root folder that contains only files that you have added. If you added none, it will be empty.
4. Run Setup_Prepar3D.exe in your decompressed download from your P3D account as an administrator.
Make sure that the target directory is the one you are left with after the uninstallation.
Unless you installed to the default location, you will need to make a change.
Wait until the process is complete. You will not be asked to activate P3D again.
If you had everything installed inside the P3D folder,
Global Base must be uninstalled and installed again.
You must run Verify files for all open LC products.
You must run verify files for the Orbx Libraries.
For good measure, also run Sync Simulator.
To find Sync Simulator, click Settings -> Help -> Sync Simulator.
If you had everything installed outside the P3D folder, then this is the advice from Ben.
If you have installed your Orbx products into a library (i.e., outside the simulator), when you uninstall v5 your Orbx products will still remain installed, but just not linked to your simulator.
Then, once you've installed v5, open Orbx Central. Click Settings -> Help -> Sync Simulator. That will edit your Prepar3D add-ons.cfg, re-adding the Orbx library path and automatically linking your Orbx scenery again.
Once you have completed these steps, you must at least rename or delete
C:\Users\your user account name\AppData\Roaming\Lockheed Martin\Prepar3D v5\Prepar3D.cfg file
and let P3D build a new one.
You might need to delete the P3D v5 shaders at C:\Users\your user account name\AppData\Local\Lockheed Martin\Prepar3D v5\Shaders.
You can delete the entire Shaders folder.
Ideally, you should run the P3D\Delete Generated Files batch file but it will leave every setting back at default.
If you have spent time on controls settings, for example, you will lose them all. It's up to you.
If you do decide to run the batch file, be sure to run P3D at least once after that and before you run Settings -> Help -> Sync Simulator.
Based on my own experience, doing all of this and nothing else will leave you with all the features of the Hotfix working as promised...and your Orbx products intact.
Following a customer question, these are the four entries referred to in step 2.