Is it possible that the ones that do not work correctly were made with a version of PP for Windows that is in advance of the Mac version?
Of course, that would not explain why they open correctly on your wife's PC.
Are you updating your copy of Office?
On your new iMac, you should have a trial copy of iWork which contains a program called Keynote. This is a presentation application that is considered, by some, to be better than PowerPoint. It is able to open PP files and display them. Try opening one of the offending PP attachments using Keynote and see what happens.
Currently, Office for Mac is not Universal Binary so it is not running at its best on your machine.
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My computer is the latest Imac 24" purchased last month. I'm using ms office for mac 2004, My problem is annoying when I get pps attachment from my friends. Most of them open fine, but others will not open any further than the First page and freeze there. Most of them have a music background on them . I have forward them to my wife PC and they open good. So I have to do force quit Power point which at that time is not responding. I have tried to save them and play them from document and it is the same thing.Can anybody help.Thanks

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