Wait a minute? Are you hoping to use
System.Windows.Forms
in ASP.NET? If so,
just forget it; probably you have no idea how ASP.NET works.
ASP.NET makes no assumption on the software installed in client. It normally generate plain HTML with Javascript, CSS and other resources readable with a general-purpose Web browser. There is nothing to host your Forms. All .NET code is hosted only on server side; but if you, quite formally, host the Forms on server-side, who will see them? Did you get the hint? If not, start reading about what ASP.NET does, but start from the very basic ideas behind HTTP servers and clients. See
http://www.asp.net/get-started[
^].
—SA