In Windows Vista, Microsoft made one often-overlooked change that has proved to be a significant annoyance for those who use older Windows programs --- the operating system no longer will read Help files in .hlp format. So if you have a program that uses .hlp files, or if you download and informational files in .hlp format from the Internet, you're out of luck.
That is, unless you use this program. Download it, and it will let you read .hlp files. No, it's not an earth-shaking download, but it certainly is useful.
--Preston Gralla
Note: this download will take you to the developer's site.
