How to shut down a frozen program
Have you ever been stuck because a program has stopped working, its window frozen and the program won't close? To me it happened several times on both Windows and Mac; it's annoying, but it's easily solved. All you have to do is click on a combination of three keyboard buttons, select the program you want to close in the tab that pops up and click on OK....but let me be a bit more specific. xD
Terminate process on Windows
For Windows, the buttons combination is
CTRL+ALT+DEL - to be used at the same time; this combo will open Windows' Task Manager, where you will see a list of all the programs that are currently open and in use. Select the program you want to close and click on
Terminate process; you'll notice the frozen program's windows will be shut down. All you have to do is restart the program, and you'll be able to continue your work.
Force quit a program on Mac
The buttons combo for macOS is
CMD+ALT+ESC - again, to be clicked at the same time; it will open the Force Quit Applications tab, where you have the list of all the currently open apps. Click on the app you want to close and click on
Force Quit; the app will be shut down - you will no longer see the small "open program" indicator dot below the program's dock icon - and you will just have to reopen the app to keep working.