How do I make the computer's internal speaker beep in C# without external speakers?
In .Net 2.0, you can use Console.Beep().
// Default beep Console.Beep();
You can also specify the frequency and length of the beep in milliseconds.
// Beep at 5000 Hz for 1 second Console.Beep(5000, 1000);
For more information refer http://msdn.microsoft.com/en-us/library/8hftfeyw%28v=vs.110%29.aspx