Now see if all your accessories work (scanners, cd burners, etc...) These didn't work when I first installed Win2K, but after driver updates everything is now running beautifully. Also, try to run your favorite games. I've had NO trouble running any game in Win2K so far, even DOS games - can't understand why everyone says Win98 is better for games. Win2K loves lots of RAM so stock up!
The only thing I hate is how slow the Add/remove programs window loads up. I've also had a few bogus entries of programs that I couldn't uninstall but remained in my add/remove program list. Took a lot of searching through the registry to get rid of those...