This website says that the minimum system requirements for Win 2000 Pro are:Minimum Requirements
Computer/Processor 133 MHz or higher Pentium-compatible CPU.
Memory At least 64 megabytes (MB) of RAM; more memory generally improves responsiveness.
Hard Disk 2 GB with 650 MB free space.
CPU Support Windows 2000 Professional supports single and dual CPU systems.
Drive CD-ROM or DVD drive.
Display VGA or higher resolution monitor.
I am running it with the latest service pack Version 4 on a P4 with 512megs of Rambus memory and 128 Meg Video card. It runs terrific I love Win 2000 pro, it seems like a very stable reliable operating system. Hope this helps.