The term 'Go Back!' on a PC can be accomplished by using two crossword solutions: UNDO (4 letters) and ESC (3 letters). UNDO is a command that allows the user to reverse the last action taken, while ESC is a key on the keyboard that can be used to exit out of a program or cancel an action. Both of these commands are useful for quickly reversing mistakes or exiting out of a program without having to save changes.