qui mando tutto il codice che in pratica è tutto tuo
a parte qualcosa e funziona bene se non fosse che non
sempre si apre subito il sito allora ho aggiunto la
riga

codice:
If New System.Net.WebClient().DownloadString("http://tycho.usno.navy.mil/cgi-bin/t...ains("!DOCTYPE") Then
poi ricavo ora, minuti e secondi in n1,n2,n3

qui tutto il codice
codice:
Imports System
----------------------
Public Structure SYSTEMTIME
    Public wYear As UInt16
    Public wMonth As UInt16
    Public wDayOfWeek As UInt16
    Public wDay As UInt16
    Public wHour As UInt16
    Public wMinute As UInt16
    Public wSecond As UInt16
    Public wMilliseconds As UInt16
End Structure
-------------------------
Public Class Form1
    Declare Function GetSystemTime Lib "Kernel32.dll" (ByRef lpSystemTime As SYSTEMTIME) As UInt32
    Declare Function SetSystemTime Lib "Kernel32.dll" (ByRef lpSystemTime As SYSTEMTIME) As UInt32
    Dim n1, n2, n3 As Integer
--------------------------------------------
    Public Sub GetTime()
        ' Call the native GetSystemTime method
        ' with the defined structure.
        Dim st As New SYSTEMTIME
        GetSystemTime(st)
        ' Show the current time.
        MessageBox.Show("Current Time: " & st.wHour.ToString() _
            & ":" & st.wMinute.ToString())
    End Sub
----------------------------------------------
    Public Sub SetTime()
        ' Call the native GetSystemTime method
        ' with the defined structure.
        Dim st As New SYSTEMTIME
        GetSystemTime(st)
        st.wHour = n1
        st.wMinute = n2
        st.wSecond = n3

        ' Set the system clock ahead one hour.
        'st.wHour = Convert.ToUInt16(((CInt(st.wHour) + 1)) Mod 24)
        SetSystemTime(st)
    End Sub
----------------------------------------
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim gs, ns As String
        Dim nn, n4 As Integer
        Dim sourceString As String
        If New System.Net.WebClient().DownloadString("http://tycho.usno.navy.mil/cgi-bin/t...ains("!DOCTYPE") Then
            sourceString = New System.Net.WebClient().DownloadString("http://tycho.usno.navy.mil/cgi-bin/timer.pl")
            gs = sourceString.Substring(1, 200)
            nn = InStrRev(gs, ",")
            ns = Mid(gs, (nn + 2), 8)
            n1 = Val(Mid(ns, 1, 2))
            n2 = Val(Mid(ns, 4, 2))
            n3 = Val(Mid(ns, 7, 2))
            n4 = n1 + 2
            TextBox1.Text = n4.ToString("00") & ":" & n2.ToString("00") & ":" & n3.ToString("00")
            SetTime()
        End If

    End Sub

End Class