Upgrade from ME to 2000

Ive just got a new preinstalled PC, for various reasons I would like to run Win2000 instead. Q1: How much pain is the upgrading proces (can I instal Win2000 upon ME, or do I have to make a clean install from scratch), what about HW compability (Not that I am impressed by ME after installing into on my old). Q2: What impact will Win2000 have upon my ability to run games?