BibleWorks 7 Revision 2 and later are 32-bit applications, but they will install to and run under 64-bit versions of Vista and later versions of Windows.
Though BibleWorks 4 and BibleWorks 5 have been found to install and run in the 64-bit environment, we cannot guarantee that this will always be the case. If these BibleWorks versions will not work as expected, one will need to consider use of Virtual PC or XP Mode. (See "Can I Run Early Versions of BibleWorks in Windows Vista or Windows 7?" )
BibleWorks 3.x is a 16-bit version of the program, and will not install to the 64-bit environment. To use one of these BibleWorks versions in a 64-bit environment, it will be necessary to introduce virtualization in some capacity. For more information about this see What are Virtual PC and XP Mode, and What Will They Do for Me? for additional information about this.