Outlook 2003 shows 2 copies of same data file

I've just installed Office 2003 on a new computer. I
transferred the .pst file to the new computer, deleted
the Outlook.pst created when Outlook first started and
replaced it with the Outlook.pst file from the old
computer. That worked OK. But now the Personal folders
shows up twice in the folders' list, and I can't remove
one of them. If I make a change in one of them the change
is reflected in the other. This seems to cause problems
with favorite folders showing up twice (e.g. "Inbox"
and "Inbox in Personal Folders") and also under contacts,
it shows "Contacts" and "Contacts in Personal Folders".
These are identical. It also causes the address book not
to know which of these to use, and I get an error
message. Under both of them when I right-click "Close
personal folder" is greyed out.
Please can someone help me to resolve this problem. Thank
you.

Jock