Private Declare Function GetForegroundWindow Lib "user32.dll" () As Int32
    Private Declare Function GetWindowThreadProcessId Lib "user32.dll" (ByVal _
      hwnd As Int32, ByRef lpdwProcessId As Int32) As Int32
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
    System.EventArgs) Handles Button1.Click
        Me.TopMost = True
        Dim hwnd As Integer
        Dim id As Integer
        Dim p As Process
        While True
            hwnd = Me.GetForegroundWindow()
            Me.GetWindowThreadProcessId(hwnd, id)
            p = Process.GetProcessById(id)
            If Not p Is Nothing Then
                Me.ListBox1.Items.Add(String.Format("Prozessname: {0}" & _
                  "Prozessid: {1}", p.ProcessName, id))
                Threading.Thread.Sleep(1000)
                Application.DoEvents()
            End If
        End While
    End Sub