Windows XP x64 Pro Corporate

Hardware requirements: AMD64 CPU/512MB RAM/1.5GB HD

Windows XP Professional x64 Edition is designed to meet the demands of
customers who require large amounts of memory and floating point
performance in areas such as mechanical design and analysis, 3-D
animation, video editing and composition, and scientific and high-
performance computing applications.

This is the corporate version, so no activation is required.