default button? well.. there are 'reset' and 'clear' depending on the setup panel.

of course, you could just exit keyclone, delete the keyclone.ini file... then restart. that would be resetting to defaults.

as for your drop in fps.. there are numerous potential factors.
  • memory usage
  • power supply
  • video cards
  • video settings
  • a surge could have fried something
  • in-game detail settings could be set to max (most likely the case)