You need to install the additional content. If you bought a boxed product this will be on one of the DVD's. Or by download from http://www.adobe.com/special/premiereel/downloads/
Insanity is hereditary, you get it from your children
Thanks nealeh. I appreciate it.
Contents are also removed with uninstallation of PRE. You might have uninstalled PRE and then installed it again. In that case contents are removed but needs to be installed again after main PRE installation as rightly pointed by Nealeh.