Caffeine 1.1

Prevent your PC from activating a screen saver or locking If you have problems with your PC locking or going to sleep, caffeine will keep it awake. It works by simulating a keypress once every 59 seconds, so your machine thinks youre still working at the keyboard, so wont lock the screen or activate the screensaver.
The icon is shown above - its the leftmost one in the task tray, and this is all you see. Double-clicking the icon empties the coffee pot (thats what the icon is) and temporarily disables the program. Double-clicking it again refills the pot, and will keep your machine awake.
Of all the key presses available, shift is probably the least intrusive, and least likely to interfere with your work.
Now you may prevent your PC from starting the screensaver or locking with the help of the small but smart Caffeine.