Outlook 2010 - I have one email (spam) that I cannot get deleted from my Deleted Items folder. I can move it to another folder and it will delete and be moved back to the deleted folder, but will not delete from the deleted folder. Subsequently I can't select all and delete everything from that folder; must hold control and select all other items to delete and then hit delete. How do I get rid of this one spam e-mail that will not delete?? When I try to delete it, I get the message, “An error occurred in the underlying security system. An internal error occurred”

Thanks.