Did you own a previous version of Elements with an Organizer catalog? If not, have you actually imported any files into your catalog? The Organizer is not a file browser. It is a catalog of files stored on your computer. Those files need to be imported into the catalog before you can see anything.
If you have in fact imported files into a catalog, there is an option to clear any filters in the top right of the window.
If that doesn't fix the problem, make sure that in the View>Media Types menu, you have all the necessary items checked.