I assume you're saying you have your email in Microsoft Outlook and you want to get rid of Outlook and downgrade to Outlook Express.
Why?
What would you want to go backwards?
I notice that you already have a Gmail account, so perhaps this is what would suit you much better. (For instance, you'd be able to collect or check your mail anywhere in the world.)
Export and Backup Emails from Outlook to Gmail Online
How did I find that? I used the Help function in Outlook and searched for
EXPORT. You should try it.
Paul Zucker