Symptoms
If you try to display the Help file from Metafile Companion (or any other Windows program that uses uses the WinHlp32 engine), an error message ("Failed to launch help.") appears and the help is not displayed.
Cause
The Microsoft Vista team thought it would be a "good idea" to retire the WinHlp32 engine. For more details, see:
Microsoft KB article 917607: Windows Help program (WinHlp32.exe) is no longer included with Windows
Work-around(s)
Fortunately, Microsoft quickly discovered the error in its ways and provides an update for Windows Vista:
Windows Help program (WinHlp32.exe) for Windows Vista
Installing this update solves the help problem.