Write this code to your global.asax
Sub Application_Start(ByVal sender As Object, ByVal e As EventArgs)
Application.Lock()
Application("counter") = Application("counter") + 1
Application.UnLock()
End Sub
and write these lines in your default homepage
<%
Application.Lock()
Application("counter") = CType(Application("counter") + 1, Int32)
Application.UnLock()
%>
Everything will be fine then.