To install zombiecraft on windows:

  1. Go into the start menu and "search" %appdata% locate the .minecraft folder
  2. Backup any and all saves, texture packs, and mods you wish to keep. Delete the .minecraft folder
  3. Launch minecraft from the file you (probably, pirate) downloaded from the minecraft site.
  4. After successful launch, run the zombiecraft launcher and use it up untill you play a map
  5. Reinstall all mods to .minecraft
  6. Place saves back in saves folder, and texture packs in the corresponding folder

When downloading fresh zombiecraft,it will install automically during launch.