I love fakeupdate.net - that's the way I teach my colleges to lock their screen when they leave the room.

Yesterday I made a Windows 98 screen, turned off the other monitor and disabled the keyboard. First my college was so cool and said: "I know this already just press f11" then he freaked out why this isn't working and wanted to call the support. Was a funny day.

I don't get it. Why make a win98 screen if the monitor is turned off?

This always fun. When the target would come back to their computer I would always tell them "Dude, this isn't good. Ops told me that there have been issues with the upgrade rollout and if this happened randomly there's a good chance your hard drive will be corrupted. You'd better run over there right now and get someone on this immediately!" And then they would go and drag an unsuspecting ops guy into the mix, it was the best. Now I work remotely though... No more pranks.

How do you disable the keyboard? Just unplug it?

@DeadInside There were two monitors, one he turned off and the other was displaying the win98 update screen

Start chrome with the --kiosk parameter, this way Chrome automatically starts full screen, and F11 won't work.