I found this in the help as I have(but don't use) 2003 also:
Global changes to the Reading Pane, with the exception of options set in the Reading Pane dialog box, cannot be made; you must make them individually for each folder. To make a global change to Reading Pane options, on the Tools menu, click Options. Click the Other tab, and then click Reading Pane.
I don't have WIN7 at work yet.
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