If the mail doesn't work even after uninstalling avast and restoring the account settings, I really doubt that you can blame avast for it. Outlook Express provides some logging feature, you can turn it on in menu Tools->Options->Maintenance->Troubleshooting/Mail and then watch the file pop3.log (smtp.log). Their location on my computer is: C:\Documents and Settings\[username]\Local Settings\Application Data\Identities\{....}\Microsoft\Outlook Express.