Adding Icelandic to your languages should allow you to remove it again.
Internally, keyboard layout configuration is still stored in the same place in the Registry as before and doesn't really have a relationship with the Windows language list.
Open regedit and navigate to HKEY_CURRENT_USER\Keyboard Layout\Preload, then delete the languages you don't need – the language identifier for English is 0409, Icelandic is 040f, Japanese is 0411 (related list). See also these instructions.
