Look and see if you still have the .pst file for that account. Might be in
\Documents and Settings\UserId\Local Settings\Application
Data\Microsoft\Outlook or just do a search for *.pst on your box, it should
list any .pst files. If the .pst file exists, copy it somewhere safe and
recreate the account, then copy it into the above folder for that account. If
no .pst file, did you have a backup?