Some of the possible reasons why an application stops responding are as follow: a conflict between two software or hardware resources, lack of system resources, or a bug in the software or drivers.
When a program stops responding, any work that has not been saved will more likely be lost when the program is closed. Unfortunately, there is no alternative.
It can easily be fix by pressing the CTRL + ALT + DEL keys on your keyboard to open the Task Manager window and then click the "End Task" button to terminate the program. If another window opens, click the "End Task" button again to confirm stopping that program.
If the program still stops responding, an important file in the application may have been corrupted, reinstalling the application may fix the problem.