uses
  Registry, windows;

// Показать или скрыть диалог dial-up
function DUNDialDefault(Hide: Boolean): Boolean;
var
  Reg: TRegistry;
  TempResult: Boolean;
  name, con: string;
  ASW: Integer;
begin
  Reg := TRegistry.Create;
  Reg.RootKey := HKEY_CURRENT_USER;
  if Reg.OpenKey('\RemoteAccess', False) then
  begin
    TempResult := True;
    name := Reg.ReadString('Default');
  end
  else
    tempresult := False;

  Reg.Free;
  if TempResult = True then
  begin
    if Hide = True then
      ASW := SW_HIDE
    else
      ASW := SW_SHOWDEFAULT;

    con := 'rnaui.dll,RnaDial ' + name;
    ShellExecute(0, nil, 'rundll32.exe' , PChar(con), 'C:\windows\', ASW);
  end;
  Result := tempResult;
end;

InternetAutoDial (INTERNET_AUTODIAL_FORCE_ONLINE, handle);