If you uninstall Outlook Express, you will lose your e-mail <b>configuration</b>, not your e-mail address. If you are going to uninstall it, copy all of your configuration settings before doing it, so you can configure your email account after you install the software again.
Also, you need to backup your data files if you don't want to lose your e-mail messages.
P.S. Reinstalling OE could not be necessary (or enough) to solve the duplicate messages problem. Maybe someone could help you solve that problem if you provide more details.
<b>Receiving Duplicate Emails in Outlook Express</b>
When downloading email into Outlook Express there are duplicates of each message.
This can be caused by a few different reasons. One reason is because ‘leave messages on server’ is checked in the account settings of Outlook Express.
The other possibility could be the file named Pop3uidl.dbx is damaged.
To remove the option ‘leave messages on server’ click on Tools, Accounts, a box will open up labeled Internet Accounts, be sure you are on the tab labeled ‘Mail,’ highlight the mail account, next click on properties. Once you click on properties, you will click on the Advanced tab. At the bottom of the Advanced page you will see a section labeled ‘Delivery.’ If there is a check mark in the box next to ‘Leave a copy of messages on server,’ remove that check mark. If there is not a checkmark in the box, proceed to the next resolution.
To fix the problem, simply delete the "Pop3uidl.dbx" file, do a search/find for "pop3uidl.dbx". The next time you check for mail, all the messages on the server will be downloaded again, but a new "Pop3uidl.dbx" will be created that should work properly on subsequent mail checks.