uses
 MSHTML_TLB, SHDocVw_TLB;
procedure TForm1.Button1Click(Sender: TObject);
var
 ShellWindow: IShellWindows;
 WB: IWebbrowser2;
 spDisp: IDispatch;
 IDoc1: IHTMLDocument2;
 k: Integer;
begin
 ShellWindow := CoShellWindows.Create;
 for k := 0 to ShellWindow.Count do
 begin
  spDisp := ShellWindow.Item(k);
  if spDisp = nil then Continue;
  spDisp.QueryInterface(iWebBrowser2, WB);
  if WB <> nil then
  begin
  WB.Document.QueryInterface(IHTMLDocument2, iDoc1);
  if iDoc1 <> nil then
  begin
  WB := ShellWindow.Item(k) as IWebbrowser2;
  WB.Refresh;
  end;
  end;
 end;
end;