Definition - What does Three-Finger Salute mean?
The three-finger salute refers to the original PC-compatible system command to reboot or restart a computer by pressing three keys simultaneously: Control, Alt and Delete. The three-key combination is specifically designed to be impossible to execute with one hand in order to avoid the potential for accidental reboots.
Techopedia explains Three-Finger Salute
The designer of the original IBM PC, David Bradley, created the Ctrl-Alt-Esc key combination in 1980. This combination was too easily accomplished with one hand, which could cause users to reboot the computer unintentionally. Therefore, Bradley chose a combination of three keys that would be impossible to press simultaneously with one hand
The results of pressing Ctrl-Alt-Del vary depending on the system being used. In a PC with a disk operating system (DOS), the Ctrl-Alt-Del command could be executed by the basic input/output system (BIOS). This may result in a soft (or warm) reboot.
In a Windows 3.1x in 386 enhanced mode, Windows 95, 98, and Me, the keystroke combination is recognized by the keyboard device driver and responds to the LocalReboot option in the system.ini file in the [386Enh] section. If LocalReboot=Off is found, the computer performs a soft reboot.
If LocalRebook=On is found in a Windows 3.1x machine, the user if given a blue screen and the option to press "Enter" to end the application that has stopped running (if there is one), or to press Ctrl-Alt-Del again to do a soft reboot.
If LocalRebook=On is found in a Windows 95, 98, or Me machine, the system is temporarily halted and the user is given a list of the processes that are currently running. The user may then choose to end or stop any one of them. After those decisions are made, the user can again press Ctrl-Alt-Del to do a soft reboot.
Users of Windows 9x may also press Ctrl-Alt-Del a second and third time and be given options to reboot the computer, but this does not always deliver consistent results.
If Windows NT or later versions are installed, Ctrl-Alt-Del results in different options. In this case, Ctrl-Alt-Del (or Ctrl-Alt-Esc) will often bring up the task manager dialog, where the user is presented with tabs for applications, processes, performance, networking and users, as well as several drop-down menus including the "shut down and restart" (soft reboot) option.