Can 32-Bit Applications run on Windows 2003 64-Bit?
A: The short answer is yes. WOW64 (Windows on Windows 64) is a compatibility environment provided by the operating system that allows a 32-bit application to run on a Windows 64-bit operating system. For more information, see 64–Bit Windows Part 11: Windows on Windows 64.
For web applications, Windows Server 2003 SP1 enables WOW64 compatibility for 32–bit Web applications in IIS 6.0. Based on the value of a metabase property, IIS will either start a 32–bit or a 64–bit worker process. In other words, IIS 6.0 can run applications in WOW64 or native 64–bit, but not both. For more information, see Windows Server 2003 SP1 enables WOW64 compatibility for 32-bit Web applications in IIS 6.0.