How to Lock Computer Screens
If you want to step away from your computer but are afraid that little fingers might change your settings or the wrong eyes might see what's on your screen, you can lock the screen. This will add some privacy and security to your work and can give you peace of mind. You can lock your screen using a couple different methods.
Hold down the "Ctrl," "Alt" and "Delete" buttons on the keyboard. This will either open a dialog box or another window where you can select an option to lock your computer screen.
Click "Lock Computer" or a similar option. Press "Ctrl," "Alt" and "Delete" again when you return to your screen to unlock it. You may have to enter your password as well if you use one to log into your computer.
Press and hold the "Windows" button and the "L" key on your keyboard. This will lock your computer immediately.