Even if you unpublish a link to a Joomla Component the component urls can still be accessed.
To completely disable the component without uninstalling it use the Joomla Extension Manager.
In Joomla Administrator got to Extensions > Install/Uninstall
Click the Components link under the "Extension Manager" title.
Click the green checkmark in the "Enabled" column to the right of the Component. It should change to a red x.
Now the Component is disabled.
Disabled Components do not appear in the Components drop-down menu.
