Desktop Chat

I need a desktop application for support reasons. My client should press a button (located on screen) to start the chat. first, a .flv video with encoded alpha-channel (transparency) will be played. afterwards, a chat window will pop up, enabling a chat between him and me. there is only a one to one chat necessary and there is no need for specific user name, password or the transmission of files. after the chat is finished, the window will close and another .flv file will play. finally the application needs to go back to its origin, showing just the button on the desktop. the installation will be done manually and in advance. no update function is needed. attached you can find the start button, a design of a tray icon, the appearance of the chat-window and an example of a .flv file.