A family of Microsoft presentation graphics products that offer tools for creating presentations and adding graphic effects like multimedia objects and special effects with text.
This feels like a video driver problem.
Please try running PowerPoint in Safe Mode ... hold down CTRL key while starting PowerPoint. When you get a message asking if you want to start in Safe Mode, click Yes.
Then see if the problem occurs again. If it doesn't, that's a good sign that there's a video driver problem. You might then want to check with the computer manufacturer to see if there's an updated driver.