PowerPoint 2000 default dialogs

When you begin the process of opening a .ppt file, the default option is to preview the presentation in the open file dialog box. Some of our presentations are several Megs big, and take forever just to load the preview. There are other views possible in that dialog box, but by default, it previews. We’ve searched the help files for a way to change that default, but we’re unsuccessful. I’m going to give this question until Wednesday, 11-22, before rating any answers.