Vista - Sending messages through Outlook 2007

Hey guys here is a new problem with which hope someone can give me an answer
to fix it. I am running with Vista RC1 and Offce 2007. I download my emails
from a usa.net account into Outlook and I have all the setting set right, I
have even double checked them with usa.net customer service and they are set
perfectly. The problem that I have is that I can receive all my email with no
problems but I cannot send any eamils out and it is so weird because if I
send an email to myself the email will go out and I will receive it, but if I
try to send an email to anyone else; when I click the button send/receive it
will go through the process and say that the process was compleated
succesfully but the email will neve leave the outbox, thus never being sent
out, also there have been some emails that have left the outbox but they are
never received by the people I send them too. So any ideas on how to fix this
so I can send my emails and also be received? Hope someone here has the right
answer and helps me fix the problem