Need to keep your computer awake? You could adjust your power and screensaver settings, to keep the computer from going into Sleep mode and showing the Lock screen. Or you might try Caffeine.
Caffeine is a small program that you can toggle on and off easily. Its icon lives in your taskbar or menu bar. Double-click it to fill it up with coffee, and then your computer will stay on and lit, until you double-click that icon again.
For some situations, this is a whole lot easier than tweaking your settings in the Settings/Control Panel or System Preferences. If this gadget seems useful, you can download it for free for your PC or your Mac.