Razor,
Let's stay with Avast for a moment. With XP, the MPW will not appear, and configuration is different. Avast now acts as sort of a filter and the settings no longer require 127.0.0.1 or the appersand attachment (#) in the username.
Configuration should be as if Avast was NOT installed.
POP and SMTP server names should be those of your ISP and your username should be the one used with your ISP.
Now, if you are using a firewall (I hope you are), then make sure that you are not blocking any Avast request for internet access. Avast will access the internet for mail scanning as well as for updates. You probably will see ashmaisv, and ashserv and one or more avastsetup in the traffic log of your firewall (
)
I am not sure if Netscape Mail is web based or not. I don't use it. I know that it is built on Mozilla mail, so it should work. IF OE is sending and receiving, that is a good sign. It means Avast is configured and working as it should.
Do you have Avast set to insert a message into clean email both in and out?