override OnStartUp()

    {
           if(condition == true)
           {
                ProcessStartInfo p = new ProcessStartInfo("filePath");
                p.Start(); // This should wait for like say 5 seconds and then start.
                  return;   // This will exit the current program.
            }
    }

public class MyThread
{
   public static void DoIt()
   {
      Thread.Sleep(100);
      // DO what you need here
   }
}
override OnStartUp()
{
    if(condition == true)
    {
       ThreadStart myThread = new MyThread(wt.DoIt);
       Thread myThread = new Thread(myThread);
       myThread.Start();
    }
}