Simply not true. You can choose two paths, upgrade or new install. If you
choose upgrade, it will keep existing files and programs and only replace
Windows files. However, some programs may not function if they are not
compatible so you may want to look for newer versions. The backup advice is
sound.
You should also make sure your hardware meets min. requirements - the setup
will check this anyway and let you know if it will not work. But things
like free hard drive space are something you definitely want to look at
before starting.
Also, read the info in the setuptxt folder on the cd, it has valuable info
about setting up dual-boot if you choose to do that also. (run 98 and 2000
on same pc)
Finally, don't get me wrong, Windows 2000 is a great O/S, but have you
considered XP? It's basically the same as W2K but would require must less
patching after the initial install.
Good luck!