Outlook Express not responding

Hi!

I am receiving invisible messages in my Inbox.  The Inbox folder is bolded and I see the message count but nothing appears in the right side panel.  I can only view the invisible messages by using the "find"feature.  Fortunately, most seem to be spam or junk mail.  However if I should try to delete my messages, the application locks up, "not responding".  From time to time my Outlook Express will lock up when I am downloading messages too.

I have tried to reinstall the security patches and searched for newer versions.  I have attempted to uninstall and reinstall but Outlook Express appears to be incorporated into Windows XP and I do not want to reinstall my OS.  Any ideas?

Thanks!