Because the casual user is not at all familiar with the inner workings of the PC. Often the best solution is the simplest.
That is, when the files are installed on the user's machine, set the SYSTEM and/or HIDDEN attributes on the Folder. Most users would never be able to find the HTML help files in order to run them without your application.
Unfortunately, Javascript nor HTML offer the ability to test for existence of a file. But you could simply name your HTML files with some other extension that Windows would not recognize. Then the user cannot "run" them.
THOM
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