Watin "Find.ByXXX" when load different page

I have a problem with this simple code. When the page is loaded I click on the button and a "NO" appears (now there is wikipedia). Then I surf to google and I click the button again and the "NO" is still here. But the logo with ID hplogo is on the page.

If instead of wikipedia I load google first the "YES" appears.

There is no warning or error.

Im a noob on watin and probably i'm missing something simple.

Thx!

namespace watin_TEST_20
{
public partial class Form1 : System.Windows.Forms.Form
{
    private IE browser =null;
    public Form1()
    {
        InitializeComponent();
        browser = new IE();

    browser.GoTo("http://www.wikipedia.it");

    }


    private void button2_Click(object sender, EventArgs e) //Click when page loaded
    {
        browser.WaitForComplete();
        if (browser.Div(Find.ById("hplogo")).Exists) //There is google logo?
        {
            textBox1.Text = "YES";
        }
        else textBox1.Text = "NO"; //always this
    }
}
}