As far as I am aware no version of Windows 2000 was ever shipped as OEM. You had to buy it stand alone at a costs of $500 and upwards. ($500 being the bottom end version)
I believe your description refers to Windows ME (Millennium Edition) which came out around the same time. For regular users this was the upgrade from Win 98.

Win 2000 Pro was an upgrade to Win NT, then followed Win XP Pro (nothing like Win XP regular, home or business or whatever they called them).

.