The options for installing a new operating system have become a bit more complex with the release of Windows XP or the upcoming Windows.NET.
With Windows 98, SE, ME, NT, and 2000 it was possible to perform an upgrade install or a fresh new complete install from either within the existing OS or by launching the installation from a bootable floppy or CD. With Windows XP or Windows.NET, this is not the case.
To perform an upgrade install over an existing OS to Windows XP, you must launch the installation from within the existing OS. If you launch from a bootable CD (or the bootable setup floppies) you can only perform a fresh new install.
If you want to upgrade to Windows XP Professional, you can upgrade only from the following OSes:
- Windows 98 (all versions)
- Windows Me
- Windows NT 4.0 Workstation with SP6 or later
- Windows 2000 Professional (any SP level)
- Windows XP Home
It is also possible to upgrade from Windows 95 to Windows XP Professional. However, this upgrade path is not fully supported by Microsoft technical support. You should upgrade to one of the supported upgrade path options first, then upgrade to Windows XP Professional.
If you want to upgrade to Windows .NET, you can upgrade only from the following OSes:
- Windows NT Server 4.0 (or Windows NT Server 4.0 Terminal Server Edition) with SP5 or later
- Windows 2000 Server
If you have an earlier version of Windows NT Server, you can upgrade first to Windows NT 4.0 or Windows 2000 then perform the .NET Server upgrade. If you are not using SP5 or greater on a Windows NT 4.0 system, you can install SP5, then perform the .NET Server upgrade.
If you are using Windows NT 4.0 Enterprise Server with SP5 or greater, you can only upgrade to Windows .NET Enterprise Server. You cannot upgrade to Windows .NET Standard Server. This restriction does not apply to Windows 2000 Enterprise Server.
Microsoft does not support an upgrade path between a client version of Windows and a server version of Windows or vice versa. If you need to transform a client into a server, you must perform a fresh clean new full install.