To view or edit an existing Protégé-2000 project:
For Windows systems, you can also open a project by double-clicking on the pprj file in Windows Explorer.
No matter what format your project is in, you can create, open, and save your projects directly via the pprj file. You do not need to name or access other file types unless you wish to build a project.
To save the open project to disk after you have edited it, select Save from the Project menu.
Next: Saving a Project