The three-key sequence that will bring up the Task Manager or allow a user to log off or restart the computer is Ctrl + Alt + Del. This keyboard shortcut is commonly known as the "three-finger salute," and pressing it on Windows systems brings up a menu with options including Lock, Switch User, Sign Out (Log Off), Change Password, and Task Manager. From this menu, users can also access options to restart or shut down the computer, depending on the version of Windows in use.
Additionally, another useful shortcut to directly open Task Manager is Ctrl + Shift + Esc, but to access the log off or restart options, Ctrl + Alt + Del is the standard sequence.