Hi Helen,
Graham's advice is correct for Word 2003 (also known as version 11.0),
but the answer is different for Word 2002 (a.k.a. XP or version 10.0).
There, the key is
HKEY_CURRENT_USER\Software\Microsoft\Office\10.0\Word\Options
Furthermore, the entry (named PICTURE-PATH) doesn't exist in the
default installation; Word creates it when you go to the Tools >
Options > File Locations dialog, select "Clipart pictures", click the
Modify button, and select a location.
Conversely, you can create the registry entry in RegEdit.exe and it
will show up the next time you visit the File Locations dialog.
However, that method risks mistyping the path, so using the dialog is
preferable.