Hi Vocom:
Yes, this is doable in two ways:
1) On the button in the remote web-site (not hosted via Purplenova), invoke a URL on your localhost (hosted via Purplenova), with optional GET / POST parameters that you want to communicate. On your localhost, the URL should point to a web-service that takes whatever action you want it to take on the localhost.
2) Host a windows application on your local machine via Pueplenova (see tab 3, and do look at the HELP to see exactly how this is to be done). The application (will be an exe) when hosted via Purplenova gets designated a URL by Purplenova. Invoke this URL (with optional GET arguments) from the button on the remote web-site. When the button is clicked, the URL executes the application on your local machine. Again, please look at the HELP to see how the arguments are passed to this application.
Hope this helps.
Regards,
Admin