Stubborn Emails In Unread Section

I have fifteen "emails" in the unread emails box that cannot be deleted. They are somehow left over from the enormous number of folders and emails transferred to WLM from Win Mail. If I click on them, I get a "Message Cannot Be Displayed" message. They are in bold and with a little yellow envelope on their left. Many times I've marked them as read and tried to delete them. They will then turn color as if they have been read, but when I try to delete them they go back to the "unread" look. Like the old Baptist choir, they will not be moved.