To investigate missing images in a PowerPoint presentation, it’s best to first try the following steps:

1. Ensure that all images in the presentation are sourced from the same file location or domain.
2. Check the resolution of each image, and ensure that it matches the resolution of the computer that is running the presentation.
3. Check the power configuration for the hardware (e.g. Powerpoint Settings, Monitor Settings, etc.).
4. Check for any hardware or software conflicts that might be impeding the operation of the hardware.
5. Try running the presentation on a different platform (e.g. Mac, PC, etc.) to see if the issue is system-specific.

If the above suggestions do not solve the issue, it’s best to contact technical support.