I think you are using the wrong timer. Try using the System.Windows.Forms.Timer instead and use the actual tick event to perform your logic:
var timer = new System.Windows.Forms.Timer();
int track = 0;
timer.Tick += (timerObject, timerArgs) => {
timer.Interval = ((track + 1) * 100);
this.txtOutput.Text += "\r\r\n" + " this out put equal to "
+ ((track + 1) * 100);
++track;
if (track > 4) {
timer.Stop();
timer.Dispose();
this.txtOutput.Text += "\r\r\n" + " Ends x " + track.ToString();
}
};
timer.Start();