Facts about Microsoft's development of Windows 2000, the new operating system for desktop and laptop computers and computer servers.

Most complex operating system ever, representing about 35 million lines of code.

Estimated cost of development: more than $1 billion.

Time of development: nearly four years.

Anticipated street price: £123 for upgrade from Windows NT; £310 for business desktop and notebook computers; £210 for upgrade from Windows 95/ 98; £955 for Windows 2000 server, and £460 for NT server upgrade.

Benefits: handles more demanding computer jobs such as managing major websites, encryption software, power-management features for laptops.

Windows operating systems represent roughly half of Microsoft's revenues, although the company does not break out how much each platform contributes to the bottom line.

In the fiscal year to end of June 1999, Microsoft recorded revenues of $19.75 billion (€20.00) on profits of $7.79 billion.