What is WOW64?
A: WOW 64, short for Windows on Windows 64-bit, enables you to run 32-bit applications on x64 Edition. It translates applications to 64-bit, provides higher performance for 32-bit applications, and features 4GB virtual memory space for each process. WOW64 launches and runs 32-bit applications seamlessly by isolating32-bit applications from 64-bit applications. This includes preventing file and registry collisions. Console, GUI, and service applications are also supported. The system provides interoperability across the 32/64 applications for scenarios such as cut and paste and COM. However, 32-bit processes cannot load 64-bit DLLs, and 64-bit processes cannot load 32-bit DLLs.
For more information, visit http://www.digitalproducer.com/articles/viewarticle.jsp?id=32196 and http://msdn.microsoft.com/library/default.asp?url=/library/en-us/win64/win64/running_32_bit_applications.asp