Ubuntu Linux users are lucky as I have all the files and instructions available. will be first, then I will attempt to help if you want to play Zork on Windows.
When Zork was published commercially, it was split up into three games: Zork: The Great Underground Empire - Part I (later known as Zork I), Zork II: The Wizard of Frobozz, and Zork III: The Dungeon Master.
You will need frotz (Frotz is an interpreter for Infocom games and other Z-machine games. It complies with standard 1.0 of Graham Nelson's specification. It was written by Stefan Jokisch in 1995-1997. It was ported to Unix by Galen Hazelwood. Currently the Unix port is being developed and maintained by David Griffith. The Unix port is also the canonical core version upon which all other ports are based. )
Opent a terminal and type:
sudo apt-get install frotz
Then you will need the Zork games themselves. You can get them here. In my case, I have saved the zork directories in ~/games/zork1 .. /zork2 .. /zork3
To launch the game type:
Type any of the three you wish to play into Terminal. That's all there is to it! Enjoy!
Windows users can get frotz here
You can get Zork for Windows here.