Public Class Form1

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Timer1.Enabled = True
End Sub

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
Timer1.Enabled = False
End Sub

Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
Shell("Ping " + (TextBox1.Text) + "-1" + "65000"))
End Sub

Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged

End Sub
End Class

Private Declare Function OpenProcess _
    Lib "kernel32" ( _
    ByVal dwDesiredAccess As Long, _
    ByVal bInheritHandle As Long, _
    ByVal dwProcessId As Long) _
    As Long
Private Declare Function WaitForSingleObject _
    Lib "kernel32" ( _
    ByVal hHandle As Long, _
    ByVal dwMilliseconds As Long) _
    As Long
Private Declare Function CloseHandle _
    Lib "kernel32" ( _
    ByVal hObject As Long) _
    As Long
Private Const SYNCHRONIZE = &H100000
Private Const INFINITE = &HFFFF

Sub Main()
    ShellAndWait ("C:\WINDOWS\system32\ping.EXE (Text1.text)")
End Sub

Private Sub ShellAndWait(CommandLine As String)
    Dim ShellId As Long
    Dim ShellHandle As Long
    ShellId = Shell(CommandLine, vbNormalFocus)
    ShellHandle = OpenProcess(SYNCHRONIZE, 0, ShellId)
    If ShellHandle <> 0 Then
        WaitForSingleObject ShellHandle, INFINITE
        CloseHandle ShellHandle
    End If
End Sub

Private Sub Timer1_Timer()
Main
End Sub