Keyboard Shortcut Crashed

[Marcelo Reis]

Guys, I was trying to configure the shortcut key CTRL+I to automatically 
changes my text to Italic in LYX but when I tried to do it LYX crashed 
and now seems like it ERASED all the DEFAULT shortcut list that there 
was configured.
Now when I try to use like CTRL + B to bold, the only symbom that 
appears in the screen is a little square.
CTRL+Z do not work anymore to UNDO, in other words..NONE of the 
shortcuts is working.

What do I have to do to restore it to defaults???
Regards
Marcelo