For using progress bar u have to use a timer control also .
Enable timer in property box and writ code as:
private void timer1_Tick(object sender, EventArgs e)
{
int d;
for (d = 0; d<= 100; d++)
progressBar1.Value = d;
this.Visible = false;
Login l = new Login();
l.Show();
timer1.Enabled = false;
}
And for progress bar , initialize value of it to 100