Abandon Loader is a utility for Windows that simplifies configuring and loading DOS Abandonware games including classics like Dune, Kings Quest and Monkey Island.
A great dos emulator that can help you play games in Windows 2000/XP and Linux, which up until now has been a horrifying experience for everyone! It also gives you the ability to slow down and speed up games, take screenshots, and record sound.
FreeDOS is a complete, free, 100% MS-DOS compatible operating system. This will work on a wide variety of platforms and hardware setups, and is free as it is under the GNU license. If you want to have a tamper with the OS itself, feel free to go and download the source.
One of the newer Sega Genesis/MegaDrive emulators, has pretty good compatibility with the roms. The sound of this one is also really good! Will run under Windows and requires a minimum of DirectX 5, which means you will be able to use it on Windows 2000.