The Cornell Theory Center (CTC) is a center of excellence in high-performance computing (HPC) and interdisciplinary research located at Cornell University. CTC supports faculty and staff from over 100 different research areas as well as corporate clients that require leading edge computational resources. For over ten years CTC ran proprietary Unix-based systems from IBM, SGI, and others as one of the four original National Science Foundation supercomputing centers. At the sunset of its national mission, CTC began to look for more cost-effective computing solutions for its users that would provide leading edge performance while improving reliability and manageability. This paper discusses the experiences and issues CTC had moving from proprietary Unix-based systems to industry-standard Microsoft Windows 2000 systems.