I downloaded Flash Professional and there is nothing in the library, no sounds, no symbols, no buttons. (just what I've created or imported)
What do you recommend? Should I uninstall and reinstall it?
Wondering is this is common/reasonable measure to take.
The library only has what you make. You may be thinking about components, which are in the Components panel.
I have components. It's what comes pre-loaded in the library that did not install.
The library belongs to the current FLA, it doesn't come preloaded with anything.