Retrieving emails from Outlook Express

I know OUTLOOK replaced OE but I am using OE and have for years.

I have 2 "not new" pcs (A & B) running WIN XP PRO SP3. Running Outlook Express (OE) on pcB for addr Cat does a "move" of the Cat emails from the server to my OE folders of pcB.

Subsequently, running OE on pcA for Cat shows there are no new emails to download from the server.

Usually, I do all my email work on pcA and the emails reside in the various OE folders of my pcA HDD.

How can I move the downloaded emails stored in pcB folders to pcA folders so they are all together on one pc?

Where are the OE folders located on the HDD?
I have located the Inbox.dbx file on each pc.
How can I merge the Inbox.dbx from pc A and pc B into one .dbx file on pc A?