Download Caffeine

Editor: 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 you're still working at the keyboard, so won't Lock the screen or activate the screensaver.

The icon is shown above - it's the leftmost one in the task tray, and this is all you see. Double-clicking the icon empties the coffee pot (that's what the icon is) and temporarily disables the program. Double-clicking it again refills the pot, and will keep your machine awake.

By default the app starts enabled, and works every 59 seconds. There are two command line switches you can use to alter this:

xx - where xx is a number which sets the number of seconds Between simulated keypresses. This must be the first text on the commandline
-startoff - if this is found on the commandline, the app starts disabled.
Windows 98: Caffeine works by simulating left shift key down and up events every 59 seconds.
Windows 2000/XP: Caffeine works by simulating a left shift key up event every 59 seconds.

Of all the key presses available, shift is probably the least intrusive, and least likely to interfere with your work.

New command line options: V1.4

-replace
-noicon
-useshift