how to generate a prompt window

maybe I should modify question to that: I have a class library with some methods inside, and a server class to create and register channel for the class library. When the client invokes the method by remoting, I want to create an instance of another class library, and then create and register the second class library with different port number. I can create an instance of the second class library without problem, but just have no idea where I should put the code of creating and registering it. It always either has error of 'channel already registered' or the client cannot find the server (with the new port). Any helps are appreciated.

I mean a Dos window. The first prompt window is a server I'm running. After it receives some request, I want it to create another kind of server with a new port number, which runs on a new dos prompt. Thanks.

Do you mean the Dos Prompt or a dialog for prompting input?