The Help system used by Xara X, Xara 3D 5 and Menu Maker is no longer included by default in Windows Vista and 7.
However, it is possible to add support by downloading the patch available from Microsofts site;
Windows Vista - http://go.microsoft.com/fwlink/?LinkID=82148
Windows 7 - http://www.microsoft.com/downloads/en/details.aspx?FamilyID=258aa5ec-e3d9-4228-8844-008e02b32a2c&displaylang=en