In Joomla prior to 1.6 i could set a menu-item to public, and its contents: an article for example to registered.
This lead to a si
First of all you have to update your joomla installation to 2.5 (it's the latest version of joomla), 1.7 is no more supported by Joomla community.
There are several ways to set your viewing rights. K2 is a useful CCK component to do the job, also a useful technique that I use to follow is to "link" your article's categories in a menu and set specific permissions to the menu items