First, please do not post in bold! Forum etiquette defines bold style as demanding, emphatic, almost angry!
As I explained in your other thread, Photo Manager is merely a database of your images. No actual images are stored within the program, so the potentially easiest method to Delete All, I think, is to go to Database>Delete entire database. This should remove all records in the existing database. You can then start again to add your photo folders if you wish.