Selecting Input and Output Formats : Understanding Output Formats : WinHelp
 
WinHelp
The WinHelp format is a past Microsoft standard help format for Windows-based applications. The Microsoft HTML Help format has replaced Microsoft WinHelp as a standard, but some companies continue to deliver and use the WinHelp format. The RTF-based WinHelp format compiles and compresses multiple output and graphic files into a single .hlp file.
Since WinHelp is a legacy format that is no longer being developed by Microsoft, more current output formats are often more appropriate to use. If you do not want to use another format, WinHelp provides online help for applications that run on a computer running one of the following Windows operating system versions:
*Microsoft Windows 95
*Microsoft Windows 98
*Microsoft Windows ME
*Microsoft Windows NT
*Microsoft Windows 2000
*Microsoft Windows XP