iis ado.net version

Good,

I have the following code:

    private void AspNet35()
    {
        String sWebSite = "W3SVC/1";

        DirectoryEntry site = new DirectoryEntry("IIS://localhost/" + sWebSite + @"/Root");
        try
        {
            PropertyValueCollection vals = site.Properties["ScriptMaps"];
            foreach (string val in vals)
            {
                if (val.StartsWith(".aspx"))
                {
                    string version = val.Substring(val.IndexOf("Framework") + 10, 9);

                    if (version == "3.5") 
                    { 
                        MessageBox.Show(String.Format("ASP.Net Version on virtual server is {0}", version));
                    }
                }
            } 
        }
        catch
        {

        } 
    }

The idea was to check if IIS has ASP.NET 3.5 installed. Or at least check wanted the installed versions.

How can I do this?

Thank you