With the recent release of Microsoft's newest potential cash cows, Windows Vista and Office 2007, the company is expecting a wave of upgrades from users seeking the latest functionality. But what if you're not looking for new bells and whistles? What if you want to keep your old operating systems, such as Windows 2000, running as long as possible?

Microsoft isn't making it easy for you. Office 2007 and the software for the company's much-hyped Zune music player won't install on Windows 2000. As other new products emerge from Microsoft in 2007 and beyond, more and more of them are likely to leave Windows 2000 out of the party.

Which of these installation restrictions are caused by a real lack of capabilities in Windows 2000, however? Are any of them merely a "squeeze play" by Microsoft to convince buyers that it's necessary to immediately upgrade all PCs to Vista and all servers to Server 2003 or the forthcoming Longhorn Server?

One example of this conundrum is Microsoft's Windows Defender program. This antispyware program can be downloaded for free, but it will only install on Windows XP, Server 2003, and higher. The application won't install on Windows 2000, according to Microsoft's own product documentation.

Users have reported, however, that this is simply an artificial rule built into the Installshield package that copies Defender files to disk.

The installer contains a condition defined as VersionNT > 500. (Windows 2000 is technically considered version 5.0 of Windows NT.) Admins who've removed this condition using Orca, an Installshield editor, say Defender then installs and runs fine on Windows 2000. (For information on editing Installshield .msi files with Orca, see Microsoft Knowledge Base article 255905.)