ASP.NET 4 - URL Routing not working

Question

Hi all,

I have a asp.net 3.5 web site.I changed framework version from 3.5 to 4 for URL routing but routing doesn't work.I'm getting http 404 error.My codes are like this

(In Global.asax)

void Application_Start(object sender, EventArgs e) 
{
    RouteTable.Routes.Add("product", new Route("product/{kind}", new PageRouteHandler("~/product.aspx"))); 
} 

When I request this url "sitename/product/computer" I am getting http 404 the source cannot be found error page.My product.aspx page is working but I couldn't find any rationale for error

Then I created new asp.net 3.5 project and I changed its version to 4 again and It worked.

Why can't I run url routing on my old website?