When you insert slides from a file into a Microsoft Office PowerPoint 2007 presentation by using the Slides.InsertFromFile method, the slide formatting is lost.
To resolve this issue, apply the following hotfix:
2412275 Description of the Office PowerPoint 2007 hotfix package (Powerpoint-x-none.msp, Pptconv-x-none.msp): October 26, 2010
Registry key information
Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
322756 How to back up and restore the registry in Windows
After you install the hotfix package, follow these steps to enable the hotfix:
Click Start, click Run, type regedit in the Open box, and then click OK.
Locate and then select the following registry subkey: