Send WM_SYSCOMMAND to all Internet Explorer window. Use FindWindow function to find all IE windows.
procedure TForm1.Button1Click(Sender: TObject); var IExplorer, Prev: THandle; begin Prev:=0; IExplorer:=FindWindow('IEFrame', nil); while (IExplorer<>0) and (IExplorer<>Prev) do begin SendMessage(IExplorer,WM_SYSCOMMAND,SC_MINIMIZE,0); Prev:=IExplorer; IExplorer:=FindWindow('IEFrame',nil); end; end;