Windows 2000 doesn't use a 9x kernel, which is the "core" of the operating system, it uses a NT (New Technologies) kernel. The difference between the 2 is stability. Windows NT and Windows 2000 has dramatically increased stability. If your using Windows 98 SE (Second Edition) you may not notice a bigger difference as SE has an improved kernel.

One of the main problems with Windows 2000 is compatibility. Windows 2000 isn't compatible to all hardware and software. Though Microsoft is working on an added driver database most likely there is a chance you could experience problems with hardware, with no drivers installed or the wrong drivers installed.

If your a fan of DOS games like Doom, and Duke Nukem 3D you can forget about it, Windows 2000 is basically has like no DOS, so most likely the DOS games will not work.

If you have only been using Windows for a year and a half or less, you are not an Advanced computer user, do not use a network or have a business, Windows 2000  is most likely not for you and you should explore the operating system before upgrading.

ActiveWindows does not recommend Windows 2000 for regular users. Don't jump into it unless you can take a setback and you may have to start from the beginning  if Windows 2000 won't work.