Computers that are running on Windows Vista, Windows 7, Windows Server 2008, or Windows Server 2008 R2, may be unable to open Help files (.hlp) that require the Windows Help (WinHlp32.exe) program. When you try opening a .hlp file in Windows Vista or in Windows Server 2008, you might receive the a  messages in the Windows Help and Support window.

Why does not it work and how to install the help?
Microsoft has stopped including the 32-bit Help file viewer in Windows releases starting with Windows Vista and Windows Server 2008. To let customers still be able to use the legacy type help files Microsoft Download Center provides WinHlp32.exe downloads for Windows Vista, Windows 7, Windows Server 2008, and Windows Server 2008 R2. Starting with the release of Windows Vista and Windows Server 2008, third-party software developers are not authorized to redistribute WinHlp32.exe with their programs.
To install the appropriate version of WinHelp32.exe you must know your Windows version and you must be logged on to Windows as an administrator. Once you are sure of the version you have use the following links to download the WinHlp32.exe file:

Windows Vista:
Windows 7:
Windows Server 2008:
Windows Server 2008 R2:

Common issues after installing WinHlp32.exe update
Windows Update error 80070422.
If you receive the Windows Update error 80070422, while you are downloading the WinHlp32.exe update, you may have to change the Windows Update service settings, and then restart the service. To do this, follow these steps:
Go to Start menu and open the Run box. Type Services.msc and press enter. Double Click on the Windows Update service and on the General tab, make sure that “Automatic” is selected next to the Startup type. Check the Service status and make sure that the service is started. If it is not started, click on Start. Once the service starts click on OK.

Macros are disabled. By default, the following macros are disabled in Windows Help: ExecFile, RegisterRoutine, ShellExecute, ShortCut, Generate, Test, ExecProgram

Noninteractive user access has been blocked.You might find that access has been blocked to .hlp files by noninteractive users such as system processes. These user’s do not receive an error message when this error is encountered.

Drag-and-drop functionality has been disabled. Support for drag-and-drop functionality in any application might get disabled. The user’s do not receive an error message when this error is encountered.

Dependencies on “How to Use Help” files.The Help files that are titled “How to Use Help” have been removed from Windows Vista and Windows Server 2008. The following is the list of files that were removed: Windows.hlp, Winhlp32.hlp, Winhlp32.cnt, Winhelp.cnt, Nocntnt.cnt