One of my keyboard keys has fallen off. Is there any way I can remap another key to serve as that key?

PC Keyboard remapper can easily remap a key to another one on your keyboard. Dowload it here for free. Only need 4 steps to repair your keyboard. 

For Example: Key 'Q' has fallen off. We use key combination  'Left Ctrl' + '1' to replace 'Q'. ('1' will still be '1');

how to remap key Q with key combination  LCtrl+1

An efficient way to select key is clicking "Record" button to record your keystorkes. Another way is clicking "Insert" button to select key by mouse.