Problem with OUtlook 2007

NEED HELP!

I am not a pro… i do run Outlook 2007 and purchased Avast ( i m happy with it) but my emails do not send and reading web it seems the problems is from avast and firewall settings i am lost and need to send my emails, any help?

Which is your firewall?
Does your email use SSL (encryption)?
Any other antivirus installed in this machine?