Symptoms
You created a new blank.pot template as the basis for new presentations, but Microsoft PowerPoint doesn't seem to be using that file because you don't see your changes.
Resolution
When you create a new blank.pot design template (design template: A file that contains the styles in a presentation, including the type and size of bullets and fonts; placeholder sizes and positions; background design and fill color schemes; and a slide master and optional title master.), you must save it to the default folder for templates. This is the folder that PowerPoint defaults to when you select Design Template as the file type in the Save As dialog box. If you saved the blank.pot file to a different folder, PowerPoint will not find it.