Take a backup of all contact's(local), and also take a backup of your PST file.
And don't delete this folder,
C:\Documents and Settings\Thomas Langan\Local Settings\Application Data\Microsoft\Outlook
Just go to
C:\Documents and Settings\Thomas Langan\Local Settings\Application Data\Microsoft\
and rename Outlook folder to Outlook_BKP
and do the other parts..
Thanks
Saugata