By “looking in output styles” did you mean from endnote, or by looking at a folder? Modified styles would not live in the Endnote styles folder in the program folder, but in your “Documents/endnote/styles” location. Did you by any chance delete or move that folder, change machines, or change the location of the folder to pull from, in the endnote program’s preferences? Have you done a thourough search of your computer for *.ens files?