Do not give up. All may not be lost.
What is the exact wording of the message that you get when you open this previously saved closed project?
Does it say the project file is corrupt or damaged or does is say "Where is the file_____?".
What were you doing in the project immediately before the saved closed of the project? What was the size of this project when saved closed?
Did you work with the project with the AutoSave feature enabled (Edit Menu/Preferences/AutoSave)? If so, have you gone to the Adobe Premiere Elements AutoSave Folder and tried to use one of the AutoSaves in order to save all or most of your project?
By default, the Adobe Premiere Elements AutoSave Folder is found Libraries/Documents/Adobe/Premiere Elements/13.0 (in your case), and in the 13.0 Folder is the Adobe Premiere Elements AutoSave Folder. Right click the most recent AutoSave file in that folder, select Open With, and select Adobe Premiere Elements 13.
Please review and consider, supply more information, and then we can decide what next.