what is your Windows version? XP?
a proper un-corrupt version of Windows should not have a problem with this, because the .hlp format is supported with Windows right out of the box. So if it is giving you problems, you may have to find out on Microsoft's website how to correct it, or re-install Windows (if you know how to do that).
.hlp files are not text-based files, so you cannot read them with a text editor.