How to Open Help Files (.hlp) with WinHlp32.exe in Windows 7, Vista, Windows Server 2008
Microsoft has dropped support for legacy Windows Help files, which ends with .hlp file extension starting from Windows Vista and continues in Windows 7. If you attempt to open a Help file, having .hlp file extension, in any Vista, 7 or Server 2008, you will get a dialog box asking which program to be used to open it instead. Microsoft decided to remove support for legacy help files as there was no development done for and it was not updated for many years WinHlp32.exe.
Since, there are still a lot of application software and legacy programs which provides help files in .hlp format, Microsoft, for backward compatibility has made available Windows Help program (WinHlp32.exe) for Windows Vista, Windows Server 2008 and now for Windows 7.
A genuine validation is performed before you can download WinHlp32.exe, if downloaded from Microsoft Download Center or users can download using the direct download links given below (direct download links available only for Windows 7 users).
Users who want to view .hlp files in Windows 7 need to download the Windows Help Program (WinHlp32.exe) separately from the following direct download link:
Windows 7 32-bit (x86) and 64-bit (x64): Windows6.1-KB917607-x86.msu
The Help program seems to be the same for 32-bit and 64-bit editions of Windows 7.
Microsoft Download Center Links:
Download Windows Help program (WinHlp32.exe) for Windows 7
Download Windows Help program (WinHlp32.exe) for Windows Vista
Download Windows Help program (WinHlp32.exe) for Windows Server 2008