A family of Microsoft word processing software products for creating web, email, and print documents.
Perhaps just a timing issue. If you press Alt alone, then you get the new (Ribbon) accelerator keys. If you press Alt simultaneously with one of the accelerators for the old menu bar (File Edit View Insert Format Tools Table Window Help), then you will be able to use those accelerators, but you will need to immediately add the letter(s) for item(s) on those menus. In the example, it was Alt+O, S to open the Format menu and select the Change Case item to open that dialog.