Answer: Here's your handy-dandy guide to Microsoft operating systems present, past and future.

There are three streams of operating systems at Microsoft.

The first is Windows 95/98. There are four versions of Windows 95, each basically a fix from the previous one. Two were available in retail. Two could only be obtained through the purchase of a new computer.

There are two versions of Windows 98. The initial release and the SE or Second Edition version which again is a fix to the first version with some new features. These operating systems are designed with the home consumer in mind.

The business line of operating systems at Microsoft was dubbed NT. Early on, Microsoft said it meant "New Technology." Now they say it's just a nameplate and has no meaning.

NT was designed to be an office version of Windows and consists of server and workstation versions. A server, for the uninitiated, is a computer that is a data traffic cop on a network. When you ask for your e-mail it comes from a server. When you ask for a Web page it comes from a server. When you print at your office on another person's printer via the network, a server handles the transaction. NT is currently at version 4.0.

NT Server can be used with NT Workstation or Windows 9x (x refers to either 5 or 8 in 95 or 98).

The third variety of OS is Windows CE, which is Microsoft's handheld operating system for palm-sized devices.

Essentially, Windows 2000 is Windows NT 5.0, and so it can be considered an upgrade from Windows NT 4.0.

Windows 2000 will not be a direct upgrade from 9x-based Windows products. "As far as Windows 98/98 SE are concerned, progressive versions will be released until such time as they converge with Windows 2000," said Erik Moll, product manager, Business Windows, at Microsoft Canada.

Windows 98/98 SE is built on the older 9x technology, which mixes 16-bit MS-DOS functionality with the more robust 32-bit Windows functionality. The "bit" measurement refers to how big the chunks of data are that move like traffic through the computer's bus (or internal pathways) when a program is run.

An upgrade from Windows 98/98 SE to Windows 2000 would not be a seamless upgrade as from NT 4.0 to Windows 2000 because the two technologies (9x and NT) are different.

Third-party software developers are working on products that will allow the conversion though. As usual, a clean installation (after reformatting the hard drive) will be the easiest way to migrate to Windows 2000.

To add to the confusion, the follow up to Windows 9x, is code-named Millennium. A final name for the new consumer OS hasn't been selected. A beta version to be shipped to 5,000 testers is expected any day now. Microsoft says the software will offer four areas of improvement: PC simplicity, greater digital media and entertainment support, home networking support, and improved online access from the desktop.

After the Millenium OS, the Windows 9x line of operating systems will be phased out and will be replaced by Windows 2000 technology.

Of great interest in the OS is a new "System File Protection" tool which is supposed to help stop the corruption, overwriting, or deletion of essential system files. It's designed to stop new programs overwriting shared files available to Windows and other software with older file versions. Improved stability, a faster startup, and better use of memory are also promised features.

Microsoft also sent a nearly final version of Windows 2000 (what they call "Release Candidate 2") to 650,000 beta testers in September.

Word on the street is that Windows 2000 will be out the door by the end of the year.