How to creat an Auto Reply for a Chat Window?

Edited again:

Hey everyone. I am working on this project to create an Auto Reply for a PM Window - Chat Software.

Now how can I create a Timer or a Project that waits for A Message or for a response. Or maybe how can I create a a simple auto responder when I recieve a chat message! I know that I the Class is Important for the Pm Window or the Chat Software, But I only want to know how to create the Response with a Timer maybe,

If there is another or better way to create and Auto-Reply for a Chat without using a timer, then I will be more than happy to know.! Thanks a Lot in Advance..