unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Timer1: TTimer;
    Button1: TButton;
    Label1: TLabel;
    procedure Timer1Timer(Sender: TObject);
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  h,n,s,m,a:integer;
  hh,nn,ss:string;

implementation

{$R *.dfm}

procedure TForm1.Timer1Timer(Sender: TObject);
begin
 m:=timer1.tag+1;
           timer1.Tag:=m;
           n:=m div 60;
           s:=m mod 60;
           h:=n div 60;
           n:=n mod 60;
            if n < 10 then
             nn:= '0' + inttostr(n)
           else
             nn:=inttostr(n);
           if s < 10 then
           ss:='0' + inttostr(s)
          else
           ss:=inttostr(s);

           label1.Caption:=nn + ':'+ ss;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  Timer1.Enabled:=true;

  //timer1.tag:=(0+1);
end;

end.