This thread is getting out of hand.
The purpose is to help the OP. The problem the OP has is related to the problems many others have with the AT&T SMTP protocol.
I have my own SMTP servers available to me, but I can not use them with my AT&T account. When I had Comcast I could SMTP all day long with no problem. I even forgot what e-mail Comcast gave me. On the other hand, AT&T wants you to use their email as your default and maybe only service. It is posible, but AT7T is loath to ever let you use some other SMTP other that what they have. The SMTP requires specific ports that are blocked ny ATT servers.
Here are his options:
- Call AT&T and do as they say.
- Do all email with web mail only.
- Get an account with somebody else.
He has already called AT&T.
Apparently they can not help him with Windows 7.
There may be third -peaty solution. But at the point The OP is likely fed up and does not wish to pursue this.