Since upgrading to Microsoft Office 2007 I now have trouble reading PowerPoint documents from a particular client.
Before I upgraded, I had no troubles reading their PowerPoint.
Now, I have missing fonts and graphics - so much so that many pages are blank, or filled only with a few dots and lines.
It is only happening with this one client - I have not had dfficulty reading older PowerPoints from others.
I don't have any problems with Excel or Word documents, only PowerPoint.
I have not been able to find documentation on this at the Microsoft support site, or via Google.

What version of Office are you running? If other Office 2007 clients can view these, then something went wrong with your installation and you might want to remove it and reinstall it as an experiment.

Find out what this client is running. He might be using OpenOffice.

Did you install the Office 97-2003 compatibility pasckage when you installed 2007? If not, the file format is foreign to 2007.

How did you just now get Office 2007? We can't get anything but 2103 here.

Have you tried the built in file repair process. It is an option when you use the file open dialogue box, there should be a drop down on the Open button that has Open and Repair. Or try PPTX Repair Kit. Link