Mail won't go to "Sent Mail" Mail is stuck in outbox.

[David]

So,
for the last week my mail in outlook 2000 (windows 2000)
won't leave the outbox after it is sent. it gets sent
successfully and I get responses from the people I send it
too, but it just stays in the outbox. have had some
occasional problems that I know about that may or may not
be related: some of my sent mail ends up getting sent --
or at least received -- several times and other times it
is never received by the recipient.

any help you can provide would be greatly appreciated.

thanks,

Dave