alt+tab en alt+ctrl+del niet toelaten..

Private frmval As Boolean = True
Private Sub frmMain_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyDown
        If (e.Alt) And (e.KeyValue = Keys.F4) Then
            e.Handled = frmval
        End If
        If (e.Alt) And (e.Control) And (e.KeyValue = Keys.Delete) Then
            e.Handled = frmval
        End If
        If (e.Alt) And (e.KeyValue = Keys.Tab) Then
            e.Handled = frmval
        End If
End Sub

    Private Sub frmMain_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        AddHandler Me.KeyDown, AddressOf Me.frmMain_KeyDown
    End Sub

Private frmval As Boolean = True
Private Sub frmMain_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyDown
        If (e.Alt) And (e.KeyValue = Keys.F4) Then
            e.Handled = frmval
        End If
        If (e.Alt) And (e.Control) And (e.KeyValue = Keys.Delete) Then
            e.Handled = frmval
        End If
        If (e.Alt) And (e.KeyValue = Keys.Tab) Then
            e.Handled = frmval
        End If
End Sub
 
    Private Sub frmMain_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        AddHandler Me.KeyDown, AddressOf Me.frmMain_KeyDown
    End Sub

Private Declare Function SystemParametersInfo Lib "user32" Alias "SystemParametersInfoA" (ByVal uAction As Long, ByVal uParam As Long, ByVal lpvParam As Any, ByVal fuWinIni As Long) As Long

Private Declare Function SystemParametersInfo Lib "user32" Alias "SystemParametersInfoA" (ByVal uAction As Long, ByVal uParam As Long, ByVal lpvParam As Any, ByVal fuWinIni As Long) As Long