What it looks like is that you want to use a timer to tick on a random period.
Something like this should be what you want. wire up the event in the designer if that's how you are doing it:
private void timer_Tick(object sender, EventArgs e)
{
var timer = (Timer)sender;
timer.Stop();
//you should check how many time's you have fired and decide whether to keep going here.
timer.Interval = valueTimer.Next(10, 100);
timer.Start();
}
private void btnRun_Click(object sender, EventArgs e)
{
timer.Interval = valueTimer.Next(10, 100);
timer1.Start();
}