You try to watch the training and there is no sound, although the video works fine. This article only applies to;
Windows 98 and newer operating systems
Training CD’s produced on and before 1997

Detailed Information:

LearnKey CD-ROM Training products produced from 1997 and ealier used what is known as a ToolBook interface. Durring installation of said product, a file named MTB40.INI gets installed and is used to control some of the audio and video functions of the training. As this was designed to work primarily with Windows 95 and NT 4.0, newer operating systems including Windows 98, 98SE, 2000, Me and XP are not compatible with this type of installation. This situation results in no sound being played durring the playing of a training video.

Solution:

Download and run the following utility to get sound working properly.

Click here to download the Toolbook No Sound Fix file