The user manual file (vac.chm) is a HTML Help format file.
To view it, you must have the Internet Explorer 4.0 or later.

If you have trouble with viewing the HTML Help files, please download
an update from Microsoft (it's free). First, try the link:

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/htmlhelp/html/hwmicrosofthtmlhelpdownloads.asp

If the link doesn't work, visit the http://www.microsoft.com, paste the
string "Microsoft HTML Help Downloads" to the Search field and click
Go. Proper links will be shown.
