can't delete email

I have Outlook Express 5.02 on a G3 Mac running on OS 8.6.
I have an email that I cannot delete (it was a press release).
I have read it and it appears 'gray" in the message window (meaning it has
been read), but my Inbox folder remains bold with '(1)', indicating that 1
email message has not been read. When I delete the message it disappears
from the Inbox window and moves to the Deleted window, but when I return
to the Inbox window it reappears (and the Inbox folder stays bold
throughout th edeletion process. The message will not delete or move from
my Inbox. When I move it to another folder it moves, but also remains in
the Inbox.
Now, with this message in my Inbox, every time I try to get messages the
program crashes. Please help!