Outlook 2007 Migration problems

a client gave me 2 laptops. Both are Windows 7 Home Premium using MS Office Enterprise 2007. I copied outlook.pst and archive.pst from the old PC in the \Users\NAME\AppData\Local\Microsoft\Outlook folder and put it in the new PC's \User\NAME\My Documents\Outlook folder.
There are 3 POP3 email accounts. 2 from one ISP and 1 from another. When I initially opened Outlook on the new PC I had to create all 3 of the accounts. They are all configured [as they are on the old PC] to keep all mail on the server and only delete when removed from the deleted folder.
When I had completed the configuration of Outlook, and pressed send/receive email, it started to download email from the server. When it was all done, we ended up with dupes of all the emails.
The owner of the laptop called me up and says that one of the email addresses has no contacts [?] and that it just doesn't seem right.
We still have the old laptop.
I need to get this right, so I need to know the best practices for transferring all the email, contacts, calendar entries, tasks, etc. from one PC to another.
Thanks in advance.
Rich