Отсчет определеного количества времени

  Dim Time As Date = Now
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        For Each C As Control In Me.Controls
            AddHandler C.MouseDown, AddressOf Control_MouseDown
        Next
        Timer1.Interval = 100
        Timer1.Start()
            End Sub
    Private Sub Control_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs)
        sender.Capture = False
        Me.WndProc(Message.Create(Me.Handle, &HA1, New IntPtr(2), IntPtr.Zero))
    End Sub
 
    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        Time = Time.AddSeconds(-1)
        Label1.Text = (Format(Time, "HH:mm:ss"))
               
    End Sub

Imports System.IO
 
Public Class Form1
    Dim myPath As String = CurDir() & "\timer.my"     'сюда пишем осавшееся время
    Dim TimeToDown() As String = File.ReadAllLines(myPath)
    Dim myTime As Integer = CInt(TimeToDown(0))
 
    Private Sub Form1_Load(ByVal sender As System.Object, _
                        ByVal e As System.EventArgs) Handles MyBase.Load
        Timer1.Start()
    End Sub
 
    Private Sub Timer1_Tick(ByVal sender As Object, ,
                        ByVal e As System.EventArgs) Handles Timer1.Tick
 
        myTime -= 1
        My.Computer.FileSystem.WriteAllText(myPath, myTime, False)      'постоянно пишем остаток в файл
        If myTime <= 0 Then Process.Start("shutdown -s -t 9000")
 
    End Sub
 
End Class

Public Class Form1
 
    Dim myTime As Integer = 10800
 
    Private Sub Form1_Load(ByVal sender As System.Object, _
                   ByVal e As System.EventArgs) Handles MyBase.Load
        Timer1.Start()
    End Sub
 
    Private Sub Timer1_Tick(ByVal sender As Object, _
                   ByVal e As System.EventArgs) Handles Timer1.Tick
 
        myTime -= 1
        If myTime <= 0 Then Process.Start("shutdown -s -t 1")
 
    End Sub
 
End Class

Dim myTime As Integer = 10800

 Label1.Text = myTime

Public Class Form1
 
    Dim myTime As Integer = 10800
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Timer1.Start()
    End Sub
 
    Private Sub Timer1_Tick(ByVal sender As Object, ByVal e As System.EventArgs) Handles Timer1.Tick
 
        Label1.Text = TimeFormat(myTime)
        myTime -= 1
        If myTime <= 0 Then Process.Start("shutdown -s -t 9000")
 
    End Sub
 
    Function TimeFormat(ByVal myTime As Integer)
 
        Dim i As Integer
        Dim TimeString As String
        Dim hh, mm, ss As Integer
        Dim shh, smm, sss As String
 
        For i = 1 To myTime
            ss += 1
            If ss = 60 Then
                ss = 0
                mm += 1
            End If
            If mm = 60 Then
                mm = 0
                hh += 1
            End If
        Next
 
        If ss < 10 Then sss = "0" & CStr(ss) Else sss = CStr(ss)
        If mm < 10 Then smm = "0" & CStr(mm) Else smm = CStr(mm)
        If hh < 10 Then shh = "0" & CStr(hh) Else shh = CStr(hh)
 
        TimeString = CStr(shh) & ":" & CStr(smm) & ":" & CStr(sss)
        Return TimeString
 
    End Function
 
End Class

Public Declare Function GetTickCount Lib "kernel32" Alias "GetTickCount" () As Long
Dim StartTime As Long = GetTickCount()
'тело программы
MsgBox(GetTickCount() - StartTime)