I am trying to get my wife's WinXP ready to move everything to a new Win8.1 laptop. She has a lot of email messages in her Windows Live Mail. I was going to accomplish moving her email by changing her POP3 mail connection to the server (FastMail.fm) to IMAP and after all the messages are copied up to the server I would setup thunderbird on her new laptop to also have a IMAP connection to the server. However, I was not able to find any way to change the existing connection from POP to IMAP. So, my next idea was to create a new IMAP account in her Live Mail and manually copy all her Inbox messages to the Inbox of that account. It seemed to be doing that but when it finished I found that it had copied all her existing inbox messages to itself and now all her inbox message are duplicated!

Is there any way to delete the duplicates? Any other suggestions will be appreciated!