If you are using Windows, press Ctrl Alt Del and follow the instructions on the screen.
If these methods do not work, you may need to reset the computer.
Do not turn off the computer to exit a program or stop a command unless you have to, because the computer clears any data you did not save.
Resetting the Computer
Occasionally, you may want to clear the computer’s memory without turning it off. You can do this by resetting the computer.
For example, if an error occurs and the computer does not respond to your keyboard entries, you can reset it to reload your operating system and try again. However, resetting erases any data in memory that you have not saved; so reset only if necessary.
Caution
Do not reset the computer to exit a program. Some programs classify and store new data when you exit them. If you reset the computer without properly exiting a program, you may lose data.
To reset your computer, press Ctrl Alt Del and then follow the instructions on the screen. You can also press the RESET button. The screen displays nothing for a moment, and then the computer reloads the operating system.