Displaying a Web page from a web service

[prayag.narula]

Hi,

I am a total newbie and this is my very first web service. I want to
display a web page using my web service. Any idea how i can do this. I
tried the following code:

[WebMethod]
public void Authenticate(string cardId){
System.Web.UI.Page welcomePage = new System.Web.UI.Page();
welcomePage.LoadControl("WelcomeScreen.aspx.cs");
}

But its giving me server error 500. What can i do??