Then remove it from the registry:
HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows
Messaging Subsystem\Profiles\Outlook

Within the Outlook folder, there are a bunch of folders with long
hexadecimal values for names -- those are the ones you need to look in to
see if you can find the ghost .PST names. If you delete one of the keys and
it points to your real .PST file instead of one of the ghosts, it's not the
end of the world -- your data won't be gone. The worst you would have to do
is recreate your Outlook profile.

display theobject name!