I have a user that woks a lot with Excel and Powepoint 2007. She usually has several Powerpoint and Excel files open simultaneously and copy & paste pictures, graphs and text between those two programs.
What happen is that after a short while both Powerpoint and Excel freezes and you can do nothing but closed the programs with taskmanager and all work goes lost.
I think the problem is isolated to the Office Program because she was having this problem with an old PC and now she got a new one (corei5 2GB ddr3) and the problem is exactly the same.
The files she works with are both ppt/pptx and xls/xlsx if that has to do with it. I don't know what to check I don't find any obvious reason, she has Office 2007 SP2 on a XP SP3
There are a number of issues with charts crashing in PPT 2007, many of which were caused by SP2. You don't want to uninstall SP2, because it fixes more than it breaks. But you do need to read this blog