Parsing HTML String

Is there a way to parse HTML string in .Net code behind like DOM parsing...

i.e. GetElementByTagName("abc").GetElementByTagName("tag")

I've this code chunk...

private void LoadProfilePage()
{        
    string sURL;
    sURL = "http://www.abcd1234.com/abcd1234";

    WebRequest wrGETURL;
    wrGETURL = WebRequest.Create(sURL);

    //WebProxy myProxy = new WebProxy("myproxy",80);
    //myProxy.BypassProxyOnLocal = true;

    //wrGETURL.Proxy = WebProxy.GetDefaultProxy();

    Stream objStream;
    objStream = wrGETURL.GetResponse().GetResponseStream();

    if (objStream != null)
    {
        StreamReader objReader = new StreamReader(objStream);

        string sLine = objReader.ReadToEnd();

        if (String.IsNullOrEmpty(sLine) == false)
        {
            ....                   
        }
    }
}