To uninstall Fast File Renamer, just follow these steps:

(1) delete the entire "Fast File Renamer" program directory.
(2) remove the "Fast File Renamer" shortcuts, by:
  (a) right-clicking on the Windows start-menu button
  (b) choose 'open' in the context menu 
  (c) browse until you find the folder with the Fast File Renamer shortcuts
  (d) remove the folder.