Each program contains help files created in the old format, WinHelp, with the extension "HLP". Windows Vista and later incorporate "HTML help" instead of WinHelp, the latter that is excluded by default.
However, WinHelp still works as it did on Windows Vista and earlier, 7, 8, 8.1 and 10 as shown below after you download and install Windows Help program (WinHelp32.exe).