Caffeine 1.98

Prevent your PC from entering sleep mode, locking the screen, or activating the screensaver. The tool simulates a keypress every 59 seconds, tricking your computer into believing that you are actively using the keyboard, thereby preventing screen lock or screensaver activation. This program operates discreetly in the system tray.

Caffeine is a utility that prevents your PC from sleeping, locking or activating the screensaver. It works by simulating a keypress once every 59 seconds, so your machine thinks you're still working at the keyboard and won't lock the screen or activate the screensaver. The program runs in the system tray. Double-clicking on the icon empties the coffee pot (that's what the icon is) and temporarily disables the program. Double-clicking on it again refills the pot, and will keep your machine awake.