popup window

Hello, Does anyone have ideas about this kind of scenario? 1) Load a php page, based on whether a user is currently authenticated either: a) if not authenticated: pop up a new browser window or b) if already authenticated, proceed 2) Based on the login id of the individual that either failed to login or succeeded, you either: a) close the little popup window and load a user information page from a database on the original page. or b) close the little popup window and load an error message up on the original page. The average gray generic "enter user name and password" in IE or Netscape isn't good enough because the login page needs to have multiple options that are dynamically generated as well (login.php would be the contents of a popup) I know how to do popups with Javascript, but what I want is to use purely PHP. Is there a way to spawn a browser window from a server-side action? Thanks Dan