A couple of things to try.
Under EXTENSIONS – MANAGE EXTENSIONS remove all extensions.
With moneydance shut down rename your configuration file config.dict to say config.dict_old
Look in C:/Users/user_name/.moneydance
if Moneydance freezes, with Moneydance shut down post the errlog.txt found at C:/Users/user_name/.moneydance
Detail exactly what you were doing when the program froze.
For the Mac OS, if the window for Edit Splits is off screen the "show all application windows" should work. This is normally bound to the control-down arrow key but could be remapped in the System Preferences->Keyboard (Short cuts tab, and look at the "Mission Control" application).