One of the things we have been hearing recently is that you design your poster on your Mac at home, then email it to yourself at work where you hope to edit it on your PC. It becomes a mess! As you have discovered, PowerPoint is not terribly faithful across platforms, as well as between versions.
We have some suggestions for making this a little easier:
Do- Use Arial and Times New Roman fonts only, and Symbol for Greek letters. Staying with these fonts makes a lot of the problems go away.
Don’t- Use transparency and drop shadow effects. These are available in the PPT 2007, but they don’t save if you save it as a ppt instead of a pptx. Transparency effects also confuse printer drivers, so it’s best to avoid them altogether.
Do- Import jpg files for images whenever possible. All versions of PowerPoint know what to do with a jpg. Some other formats, especially png on the Mac, don’t make the cross platform trip.
Do- Use paste>special when importing charts and tables, and import them as an enhanced metafile. This turns them into artwork that is uneditable, but it keeps them from going wild if you change their size.
Finally, get everything together on one computer, proof it carefully, and send us the file. We’ll run it on the same program and platform you used, and the results will be perfect.