Hello,
Every our component is installed using standard Joomla! installation procedure. You can read the description
here.
If you get "Component Install: Another Component is already using directory" error this means that probably you have not uninstalled the component correctly. This is normal behavior to uninstall the component before reinstalling it. Please make sure you have uninstalled the component before install.
Uninstalling ARI Quiz component will not touch your database data.
Please let us know if you have any other questions.
Regards,
ARI Soft