Switch the Keyboard Layout To DVORAK

If you really want to screw with somebody without installing anything, just enable the Dvorak alternate keyboard layout that even most geeks aren’t familiar with. When they type, everything will go haywire.

Head into Control Panel –> Region and Language –> Keyboards –> Change keyboards, then click the Add button and pick the Dvorak layout (or any other random layout you want). Once you’ve done that, use the drop-down above to set the default.

You’ll probably want to flip over to the Language Bar tab and set that to hidden as well, so they won’t be able to figure it out easily.

Setup Task Scheduler Jobs to Launch Random Apps (or a Web Page)

Even a serious geek is going to be pretty lost on how to troubleshoot a new tab repeatedly opening to a certain page every couple of minutes, if you bury that inside the task scheduler. Just go in and create a new task, run through the wizard and pick the browser executable, plug the site name into the arguments box, and then set the schedule to repeat the task every 5 minutes.

Activate High Contrast Mode (with a Single Hotkey!)

There’s a built-in accessibility option that can be very confusing to somebody who doesn’t know how to turn it off, and it requires only pressing one shortcut key sequence:

Shift + Alt + Printscreen

That’s it. Once you press that key combo, their desktop will get flipped to the high contrast mode—you can press it again to go back to normal. The great thing is that even if their computer is locked, you can enable high contrast with the icon on the lower left corner. On Mac OS X, you can press Ctrl+Opt+Cmd+8 to invert the screen’s colors.

Set the Mouse Pointer to Look Always Busy (to Make Their PC Look Like It’s Hanging)

Nice and simple, but oh so fun! Just head into Control Panel –> Mouse –> Pointers and change the Normal pointer to the busy one. They’ll think their computer is hanging all the time, but it’s really not. For extra fun, you could make the mouse pointers gigantic.