WoW64 (
Windows-on-Windows 64-bit) is a subsystem of the
Windows operating system that is capable of running
32-bit applications and is included on all
64-bit versions of Windows — including
Windows 2000 Limited Edition,
Windows XP Professional x64 Edition,
IA-64 and
x64 versions of
Windows Server 2003, 64-bit versions of
Windows Vista and
Windows Server 2008, as well as 64 bit editions of
Windows 7. WoW64 is designed to take care of all the differences between 32-bit Windows and 64-bit Windows, particularly involving structural changes to Windows itself.