0x800CCC0E Error message

[Zuke174]

Okay, I realize that many, many people have posted about this particular problem, and I've seen many of the responses, but nothing has worked for me. Here's the exact error that I'm getting:

The connection to the server has failed. Subject 'Applicant: Design Engineer', Account: 'mail.comcast.net', Server: 'smtp.comcast.net', Protocol: SMTP, Port: 587, Secure(SSL): No, Socket Error: 10060, Error Number: 0x800CCC0E

I'm trying to use Windows Mail (2006) on Windows Vista, which hasn't given me this problem until recently. I haven't sent emails in some time, but I'm fairly sure it's worked a few weeks ago.

I spent half an hour on the phone with Comcast tech support today, to no effect. We did verify my servers were correct (mail.comcast.net and smtp.comcast.net), as well as the port 587 thing. I have used the removal tool to get rid of Norton Internet Security.

I have also tried installing Thunderbird to use as my email program instead, but that won't send either. That program gives me the message:

Sending of message failed.
The message could not be sent because the connection to SMTP server smtp.comcast.net timed out. Try again or contact your network administrator.

I've got PC Tools Spyware Doctor as my antivirus, with the email scanning turned off.

The only thing I haven't done completely is to totally repair my registry, although most of it has been taken care of by two different programs.

Is there something else I need to try that doesn't involve buying another program?