IMovie question

The easiest way is to create a new blank library and open iMovie in that one. There won't be any projects or media in it. You can then delete your old library if you really want to get rid of everything. You would lose all of your past projects (and your media unless you have is saved somewhere else). Unless you have space issues, it suggest keeping your old iMovie library. You never can tell whether you might need to reference something in your old library.

To open iMovie in a new library open it while holding down the option key. A box will appear giving you the option to create a new library.

-- Rich