Tom,
Does PM use any components of Quicktime? There are some comments in the MS Media Expression forum about the new version of QT having compatibility issues with nVidia drivers.
If the answer to the question is yes, does anyone know where you can download an older version than 7.2 QT???
Yes, PM uses QuickTime if it is installed. Note that for PM to use QuickTime, it needs to be version 7.138 or higher, otherwise PM 4.5.3 will ignore it.
How much older of a QuickTime version do you need on Vista to make it compatible with nVidia drivers?
As a test, you could just uninstall QuickTime altogether and see if that improves stability. If it doesn't then you don't need to spend time hunting down older versions of QuickTime.
HTH,
-Kirk