Downgrade to Windows Vista. GD&R

>I have tried 3 options
>
>VFP program using easymail objects to send - works on every other operating system and anywhere in the world
>
>VFP program using Chilkat software to send - works as above
>
>eudora - works as above
>
>Norton AV has been uninstalled and Firewall disabled
>
>What can I do