Option Strict On

Option Explicit On

Imports System.Runtime.InteropServices

Public Class Form1

    Private Declare Function GetLastInputInfo Lib "user32.dll" _

        (ByRef plii As PLASTINPUTINFO) As Boolean

    Private Structure PLASTINPUTINFO

        Dim cbSize As Integer

        Dim dwTime As Integer

    End Structure

    Private Declare Function SystemParametersInfo Lib "user32" _

                           Alias "SystemParametersInfoA" (ByVal uAction As Integer, _

                           ByVal uParam As Integer, ByRef lpvParam As Integer, _

                           ByVal fuWinIni As Integer) As Integer

    Private Const SPI_GETSCREENSAVETIMEOUT As Integer = 14

    Private Sub Timer1_Tick(sender As System.Object, e As System.EventArgs) Handles Timer1.Tick

        Dim oPLII As PLASTINPUTINFO

        oPLII.cbSize = Marshal.SizeOf(oPLII)

        GetLastInputInfo(oPLII)

        TextBox1.Text = CType((Environment.TickCount - oPLII.dwTime) / 1000, String)

        If (Environment.TickCount - oPLII.dwTime) / 1000 >= 10 Then

            'MsgBox("system inactive")

        End If

    End Sub

    Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load

        Timer1.Start()

    End Sub

End Class