I tried that before posting my question. It affect the size of fonts in Windows Help, but not in help for other applications - or that is my experience. I have looked at several different help files, and all of them seem to use very small fonts.
In Win 98SE and using Internet Explorer, if you go to View and alter the Text size to LARGEST, this will alter the size of the text in the RIGHT hand panel of the IE Help files. The text in the LEFT panel remains the same as before. Altering the size of the text in IE does alter the size of the Text in Outlook Express BUT only when PRINTING out the E-mails. (It does in my system, anyway.) There is also info regarding Font sizes in the Registry under HK Current User and HK Current Config. Maybe comparing the sizes you have in the Registry with someone else's listings might throw some light on the problem??