To close a programs in Windows, try clicking on the File menu and look for an option that says close or exit; if this doesn't work, click on the X icon at the upper right of the window in the title bar. The task manager can close crashed programs.
To close programs that don't close on their own or that have crashed, access the task manager. In Windows 7 and in earlier Windows versions, hold down the Control, Alt and Delete keys simultaneous and click select Task Manager. In Windows 8, Windows 8.1 and Window 10, hold down Control, Alt and Escape at the same time. Click on the name of the program using the right mouse key, and select the close or exit command.