Action after recognizing a command

Hi people

i'm new to speech development and i'm learning as i go forward.

i'm developing an application using system.speech namespace with some simple functionality.

i'm using the following method to display what is recognized in a text box, this part works fine:

        void spRecognizer_SpeechRecognized(object sender, SpeechRecognizedEventArgs e)
        {
            textBox2.Text = e.Result.Text;
        }

also, i'm using this method to create a grammar builder to create some grammars (commands)

        private Grammar CreateSampleGrammar()
        {
            Choices commandChoices = new Choices("Wikipedia", "Google", "Yahoo", "MSN");
            GrammarBuilder grammarBuilder = new GrammarBuilder("Search");
            grammarBuilder.Append(commandChoices);
            Grammar g = new Grammar(grammarBuilder);
            g.Name = "Available programs";
            return g;
        }

and when i click on the button, the grammar is loaded:

        private void button3_Click(object sender, EventArgs e)
        {
            SpeechRecognizer spRecognizer = new SpeechRecognizer();
            Grammar g = CreateSampleGrammar();

            spRecognizer.LoadGrammar(g);
        }

i should mention that before i click on this button, when i say , for example: Search Google, in the text box it appears search google ( not all of the time, but most of the times its something similar). but after i click the button, when the grammar is loaded, then, when i say for example search google, on the speech recognition bar ( on the top of screen) it displays "Search Google", but nothing is typed in the text box.

 it seems to me that, the second time when i say "search wikipeda", the engine recognize the phrase as a command, a command like "Open Notepad" (which opens notepad). correct me if i'm wrong...

if that's the case, that's what want, i'd like the application to take an action upon recognizing my command, like when i say "Search Google", with the grammar loaded, google.com should be opened in the system's default web explorer.

 how can i achieve this?

appreciating any help in advance