Windows 2000 is an operating system developed by Microsoft and targeted for workstation and server computers. Windows 2000 comes in 4 different versions, professional, server, advanced server and datacenter server. Here is how Microsoft describes the different versions. (http://www.microsoft.com/windows2000/server/howtobuy/choosing/default.asp)Product BenefitsWindows 2000 Professional Highest reliability to keep your business running Enhanced security to protect your business data Best support for mobile business computing Best platform for next-generation business technologyWindows 2000 Server Best platform for file and print, Web server, and group mail. Scales from 1 to 4 processors and up to 4 gigabytes. Reliable and available--components tested through Microsoft's Windows Hardware Compatibility Labs (WHCL).Windows 2000 Advanced Server Best platform for line-of-business and .com backend usage. Provides enhanced performance and scalability through SMP and extended memory support. Scales from 1 to 8 processors and up to 8 gigabytes. Enhanced reliability and availability--provides two-node clustering; 32-node network load balancing; components tested through WHCL.Windows 2000 Datacenter Server Best platform for large-scale line-of-business and enterprise .com backend usage. Supports server consolidation and enhanced scalability. Scales from 1 to 32 processors and up to 64 gigabytes. Maximum reliability and availability--provides four-node clustering; 32-node network load balancing; systems tested through the Datacenter HCL.As you can see windows 2000 is a very scalable operating system suitable for desktop computers as well as large network systems. Windows 2000 Professional version is suited desktop users, mobile computing and workstations, Server version is best suited for small file and print server and Advance and Datacenter Servers are designed to meet the needs of large networks. For more detailed information on features of each of windows 2000 versions you can consult Microsoft website atwww.microsoft.com/windows2000/server/evaluation/features/default.aspWhen choosing an operating system some important factors to consider are reliability, security and performance. According to Microsoft Windows 2000 is fast, reliable, easy to use and very secure. Now since this information comes from Microsoft it has to be taken with a grain of salt, however many outside sources tend to agree. One of them is www.zdnet.com which states Ms Windows 2000 is more reliable, performs better and is more secure then previous versions of windows (windows NT). According to zdnet windows 2000 is easy to setup, reliable and very secure although it requires embracing active directory, considerable management attention and significant training. According to another website (www.techweb.com) Windows 2000 performance is excellent and latest benchmarks of windows 2000 datacenter version show that windows 2000 running on Intel based systems outperforms traditional Unix/RISC systems in building more cost-effective enterprise environments. Windows 2000 is not without its faults. There had been numerous security breeches, reliability and incompatibility issues, however thanks to excellent service provided by Microsoft called windows update all known bugs have been fixed and issues resolved. Thanks to windows update Microsoft gives users easy way to keep their windows 2000 up to date on newest compatibility fixes, security and performance patches.