Below are some troubleshooting steps you can take to ensure your PowerPoint slides with charts and graphs appear properly:

1. Check that you have the latest version of PowerPoint by selecting Help and Check for Updates.
2. Check that your computer meets the system requirements for your version of PowerPoint.
3. Ensure your nested files such as graphs, charts, and images are in the same folder as your PowerPoint presentation.
4. Run the PowerPoint Save & Compress Media… tool to reduce the file size.
5. Recheck insertion steps to ensure graphs and charts are properly inserted.