Microsoft delivered Windows 2000 code to software manufacturing plants in the US, Europe and Asia on Wednesday after spending three years developing the operating system.

Deborah Willingham, vice president of the software giant's Business Enterprise division, said that although it would not be available to users until 17 February, this will enable the manufacturing plants to start duplicating disks and building boxes.

Three Windows 2000 product iterations were released, comprising the corporate desktop client, Windows 2000 Professional, Windows 2000 Server and Windows 2000 Advanced Server, the successor to Windows NT 4.0 Enterprise Edition. A fourth version, Windows 2000 Datacenter, is still in beta testing and is expected to be released six months later.

James Allchin, group vice president of Microsoft's Platforms Group, said: "Windows 2000 Advanced Server is the operating system of choice for the new generation, industry standard eight way systems. This is the product for dot coms and line of business applications."

He added that the basic Windows 2000 Server would support four way symmetric multi-processing systems.

Windows 2000 is one of the most anticipated and most delayed software projects ever. It has been besieged by numerous setbacks, including a significant redesign and the results of a management reshuffle just over a year ago.

But analysts predict - and even Microsoft officials have said - that the operating system is unlikely to fly off the shelves the way Windows 98 did last year.

According to Dan Kuznetsky, an analyst at IDC, most companies want to wait until the bugs have been fixed and they can point to others who have used it first.

"This won't be adopted right away," he said.

To help companies adjust to their Windows 2000 changeover, vendors, such as IBM, Dell and Hewlett-Packard, are providing hardware upgrades and technical support packages.