謝謝，剛去 Microsoft 的網站找，果然...

Product Information > System Requirements
http://www.microsoft.com/windowsser...qs/default.mspx
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* Important: The 64-bit versions of Windows Server 2003, Enterprise Edition and Windows Server 2003, Datacenter Edition are only compatible with 64-bit Intel Itanium-based systems. They cannot be successfully installed on 32-bit systems.