{formunuza bir timer ve label ekleyin}
var
TheTime: Integer;
 
implementation
 
function GetCounter(Second: Integer): string;
var
Minute, NewSecond, Hour: Currency;
begin
Hour    := Int(Second / 3600);
Minute   := Int((Second - (Hour * 3600)) / 60);
NewSecond := Second - int(Hour * 3600 + Minute * 60);
GetCounter := CurrToStr(Hour) + ':' + CurrToStr(Minute) + ':' + 
CurrToStr(NewSecond);
end;
 
procedure TForm1.FormCreate(Sender: TObject);
begin
TheTime := GetTickCount;
end;
 
procedure TForm1.Timer1Timer(Sender: TObject);
begin
label1.Caption := GetCounter(GetTickCount div 1000 - TheTime div 1000);
end;