Hi YS002 and welcome to our community
While it's true that Microsoft is stressing that folks
migrate WinHelp (.HLP) files to HTML Help (.CHM) format, you need
to know that
WinHelp files still "work" in Vista. Microsoft is simply
making it more painful in order to coax users to switch formats.
Older WinHelp files (16 bit) should just run fine in Vista
with no fuss. More recent WinHelp files (32 bit) will prompt the
user to download the Vista 32 bit WinHelp viewer. This occurs just
once. Once the WinHelp viewer is on the PC, the newer WinHelp (32
bit) files should also just run fine in Vista with no fuss.
Cheers... Rick