Open up your toolbox, and locate the control called "OpenFileDialog". You might have to scroll down to see it. But you're looking for this:

Properties

Private Sub mnuOpen_Click(ByVal sender As Object, _
ByVal e As System.EventArgs) _
Handles mnuOpen.Click

openFD.ShowDialog()

End Sub

The Initial Directory property.

openFD.InitialDirectory = "C:\"
openFD.ShowDialog()

The Title Property

openFD.InitialDirectory = "C:\"
openFD.Title = "Open a Text File"
openFD.ShowDialog()

Run your code again

Filter Property

openFD.InitialDirectory = "C:\"
openFD.Title = "Open a Text File"
openFD.Filter = "Text Files|*.txt"
openFD.ShowDialog()