Upgrades
Windows 2000 Professional supports the upgrade of the most recent
of the Windows-based family; this includes Windows 95 (OSR 1,
OSR 2, OSR 2.5), Windows 98 (and service pack), Windows 98
Second Edition, Windows NT 3.51, and Windows NT 4.0. Upgrading
from Windows 3.1, Windows 3.11, Windows for Workgroups,
Windows NT 3.1, or Windows NT 3.5 is not supported and will
require a clean install. Additionally, those users still using Windows
2000 Professional Beta 3 and earlier must first upgrade to Windows
2000 Professional RC2 or higher before upgrading to the official
release of Windows 2000 Professional.
Network installations of Windows 95 shared from a server are
also not supported for upgrade to Windows 2000 Professional. To
install Windows 2000 Professional on these machines, a clean
installation must be completed. Other points to remember are that
during the upgrade process Windows 2000 Professional searches
the workstation's hard drive for other installations of Windows and
will fail if there are multiple operating systems installed on the
workstation. You cannot upgrade from Windows 9x to Windows