How do I reset my libraries back to original condition? How do I reset my arduino installation back to its original state? i.e., no extra downloaded libraries, etc.  If I delete Documents/Arduino/libraries is there any other state that needs to be cleaned up?
Delete the Documents -> Arduino -> Libraries to remove all your libraries.
Delete the User -> AppData -> Local -> Arduino15 folder to remove all the preferences.
Uninstall Arduino IDE.
Install a fresh one.