ProgressBar1.Position := ProgressBar1.Position + 1;

procedure TForm1.Timer1Timer(Sender: TObject);
begin
ProgressBar1.StepIt;
if ProgressBar1.Position = ProgressBar1.Max then Form2.Show;
end;

procedure TForm1.Timer1Timer(Sender: TObject);
begin
   ProgressBar1.Position := ProgressBar1.Position + 1;
   if ProgressBar1.Position = 100 then Form4.Show;
end;