unit Unit1;

interface

uses
 Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
 Dialogs, StdCtrls;

type
 TForm1 = class(TForm)
 Button1: TButton;
 procedure Button1Click(Sender: TObject);
 private
 { Private declarations }
 public
 { Public declarations }

 end;

var
 Form1: TForm1;
 Total:integer;

implementation

{$R *.dfm}

Function EnumProc (WinHandle: HWnd; Param: LongInt): Boolean; stdcall;
 Begin
 If (GetParent (WinHandle) = 0) and (not IsIconic (WinHandle)) and 
 (IsWindowVisible(WinHandle)) Then
 PostMessage (WinHandle, WM_SYSCOMMAND, SC_MINIMIZE, 0);
 Inc(Total); EnumProc := TRUE;
 End;

procedure TForm1.Button1Click(Sender: TObject);
 Begin
 Total:=0;
 EnumWindows (@EnumProc, 0);
 End;

end.