XP Pro and dial-up

I am new to Windows XP. I have dial-up internet
and e-mail. Everything works except my outgoing
mail. It doesn’t mail! I keep getting error messages that my connection was interrupted. Is there a setting somewhere that will fix this. I’ve tried not scanning outgoing mail but it made
no difference. Also disabling firewall makes no
difference.

I’ve been tearing my hair out for so long I should
be bald soon.- Thanks