Windows comes in several versions:

• 95/8/ME old software based on 16-bit code, and with little or no security.
• 2000 and XP newer 32bit versions with enhanced security.

All versions (98/NT/2000) share the same user interface, except XP, which has a new-look with enhanced features. If you machine is older, or lower-performance, you can revert to the original interface.

Windows 2000 and XP were built with much more security in mind, and are immune to many of the simpler attacks, and security problems, that plagued earlier versions. That said, Microsoft still has a long way to go before they reach the level of most commercial versions of Linux and UNIX.

Windows-XP comes in two main flavours "Home" and "Professional", the major difference is that the security has been greatly simplified. In "Home", users can either be standard or privileged, whereas "Professional" allows far greater control. Professional can also join a "domain", and includes IIS (Internet Information Server).

Windows NT and 2000 also come in two major flavours: A client workstation, and a server. Only a server can create and manage a "domain". Windows-2003 (formally .NET) is set to replace NT and Windows-2000 servers, and will come with most of its security features installed and activated.