I've had complaints about not being able to view the powerpoint files, but I've tested them on several machines (with IE4) and have had no problems. I think there must be variations in people's powerpoint versions or configurations that are having problems.
If the file does not download and you get garbage in your Netscape window, you can download by holding down the shift key when you select the file.
This material is all copyright © by David L. Dill, 1999. Any of this material may be used if the source is acknowledged. All other rights are reserved. There is no guarantee of accuracy or completeness, however, so use it at your own risk.