Wow, 1.2 MB of a little program... Hmm.
That program simply makes a call to a Win32 function and passes it a constant SPI_SCREENSAVERRUNNING. That tricks Windows into thinking that a screen-saver is running. That tells Windows not to respond to hotkeys such as Ctrl+Alt+Del. That does not work for Windows NT, and probably won't work on XP. That was a little undocumented trick that people used on 9x/Me...
I think you can find the same program written in C++ (so it will be a few KB in size

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