Keycodes? Accessing the Insert key

[Brenton Garman]

First off, I want to thank you for so speedily answering my question, (Mike
and R.Mac)
however, let me rephrase my question: "Upon startup, I need the textbox,
without the user pressing the "Insert" Key, to have the behavior as though
the user did press the "Insert" Key.
This is for a Guitar Tab-Editor....
|- - - - - 7- - - - - -|
|- - - - - - - - - - -|
|- - - - -4^ - - - - - -|
|- - - - - - - - - - -|
|- - - - - - - - - - -|
|- - - - - - - - - - -|
See how the text moves to the right? Now I set the sellength as follows:
Private Sub RichTextBox1_SelectionChanged(ByVal sender As Object, ByVal e
As System.EventArgs) Handles RichTextBox1.SelectionChanged

Me.RichTextBox1.SelectionLength = 2
End Sub

This only works for most letters and numbers. Like "p" still pushes the text
to the right, wheras "h" won't.
So I need to be able to "Replace" selected text without moving text to right.

Thank you so much for your time.....

Brenton