How do I migrate locally saved messages out of an old Outlook account and into a new one?

Hello,

I have an Exchange account set up in Outlook 2011. There are also a lot of archived messages saved locally on the machine. 

I need to start fresh with a new User on a new machine, but then import those old archived messages into the new Outlook mail account. 

What is the best procedure for doing this?

I know there's an export option, and you can also drag and drop folders to your desktop, but what's the best way to do this if you then want to take those exported files, and re-import them back into a new Outlook account on an entirely new computer, while maintaining the original folder structure? Any time I've tried to do something like this in the past, I've ended up with missing messages. 

Any and all help is appreciated.