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