I've been struggling with the same issue ever since Office 2007 was installed at our college. At one level I do agree with Mary's answer but there are very many people who have uploaded PowerPoint presentations on our Moodle and they still need for them to work the way they expect them to.
I have today convinced our network team here to make the following registry change (as advised in a Microsoft technical post):
- Start Registry Editor
- Locate and click this key in the registry: HKEY_CLASSES_ROOT\PowerPoint.Show.8
- Double click on the Data type: REG_DWORD
Change the Value data: to 8
- Close Registry Editor
Try this on your local PC and it should fix the problem. The bigger issue is that you can't control what's happening for all your other users. For us in the college the change will be rolled out to all our users but even then we can't influence our users when they are at home.
Sorry this is a bit wordy - I do hope it helps with your immediate problem.
P.S. This is not a Moodle problem - you would hit the same problem with the presentations on any server