How to prevent ALt+F4

[Latin4567]

im making a computer locking program which makes you enter a password to close it...

i need to prevent the user from pressing ALT + F4... I tried simply modifying the keypress event but it isnt working... why? do i need to use an api or somthing?

Private Sub TextBox1_KeyDown(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles TextBox1.KeyDown, Me.KeyDown
        If e.KeyData = Keys.Enter Then
            e.SuppressKeyPress = True
            If TextBox1.Text = pas Then
                Me.Close()
            End If
        End If
 
        If e.Modifiers = Keys.Control + Keys.F4 Then
            e.SuppressKeyPress = True
        End If
    End Sub