This does not happens with Vista's Windows Mail, Can any Freepers solve this mystery???
http://office.microsoft.com/en-us/outlook/HA011394511033.aspx
Files are usually hidden, so turn on view hidden files. Copy them from your wife’s XP computer to the Vista computer per these instructions.
This always makes me a hero with my clients.
I don’t have a Vista machine handy, but I suspect you’ll get the low-down if you search the email “Help” for “autocomplete”.