The first main window in SPSS is the data editor window. It's always open whenever SPSS is run and there is a red rectangle in the top right-hand corner to identify this. There is the data view and the variable view. Both components must be saved as a single file.
The second window contains the statistical analysis. It's called the SPSS Viewer. Each of these main windows has separate and different toolbars and menus for managing the information held in them.