I seem to FUBAR my outlook all the time, like when I have to reinstall Office. When I do that, I lose all of my saved emails. This tells you how to restore your old email folder. Well, it might not be exact for you, but It will give you a LOT of help to get you on your way.
In outlook:
Tools > Email Accounts > Change account
Under “Deliver new email to the following location:”
Click on [new outlook data file], and find the good data file. You will probably have to look in:
C:\Documents and Settings\your user name\Local Settings\Application Data\Microsoft\Outlook\outlook.pst
This is a hidden system folder, so you will have to unhide it.
Then change the drop down from “Personal Folders”
To “Personal Folders File”
Follow prompts, Click finish.
File > Data File Management > delete the bad file.
Follow prompts, and close.