Microsoft Outlook Express 6 is a free, basic email program from Windows XP.
In Outlook Express, each mail folder corresponds to a single file (DBX). For example, the Inbox folder in Outlook Express is a single file, Inbox.dbx. Conversely, Ms. Outlook stores each message as an individual file.
Maximum allowed size of DBX files is equal 2 GB and that can cause some serious problems. Point is that the users often use e-mail nowadays to exchange different files with each other. You can import email messages and account information from Outlook Express into Ms. Outlook.
If Outlook Express and Outlook are installed on same computers, you need to know this information so that you can find and copy the correct folder when needed. I started it through Ms. Outlook because it was easier (in this case it was my first time using Ms. Outlook after it was installed).
For other ways can see here :
1. Click the icon Ms. Outlook 2003, will automatically check if there is an email in Outlook Express, select Upgrade form then click Next.
2. Fill in the detailed email information obtained from the email provider then Next.