Jason and I have got into more than a few discussions as to what Steve Ballmer did at Microsoft other than be their "used car salesman" type of guy. In fact, the sweatervest guy actually wrote a few piece of code as well as the dialog for the Ctrl-Alt-Delete screen found in Windows 3.1. Well done Steve. Well done.
Since 16-bit Windows applications are co-operatively multi-tasked, it is easy to determine whether the system is responding, and if not, it is also easy to identify the application which is responsible. In that case, Windows gave you options to close the non-responsive application, restart the computer, or cancel.
Source: MSDN Blog