Fuzzy means that if you want you can make a GE "game" that works in full screen and cheats that it's the correct log in screen but it's not. This you can do with GE.
But if you want to run the correct lsass.exe (login program in windows) you must create a text file and type in it this lines:
shutdown -l
cls
Then save it as bat format. For example myfile.bat. Now, DON'T open the file. Put it in the startup-folder. Now, when anyone enters your computer it will launch the myfile.bat and return to login screen.
Wait a minute, if you want to give yourself a chance to abort the login screen, you can modify the code into:
shutdown -t 5 -l
cls
Now it will display 5 seconds countdown before executing. To abort the log off, you must quickly open the command prompt
(quicktip: windows key + r -> type "cmd" and press enter)
and quickly type this code in the command prompt:
shutdown -a
It will abort the log off. You can change the 5 in any other number but make sure that you wil have time to type the command in command prompt.
EDIT: Noooooooooo! Do nothing! There seems to be an error!
Windows (at least home XP SP 2) doesn't seem to allow log off with a time period.
So you must change the code line to close the computer. Like this:
shutdown -t 5 -s
cls
Phew. I hope you didn't allready do the above code.