This is a simple but effective prank that you can do on any PC in less than 5 minutes. It creates a fake window that does not respond and looks 100% real. People think their computer is going crazy and they try to fix it by messing with the task manager, restarting, and many other crazy things.
Step 1: Print Screen
DO NOT ACTUALLY PRINT YOUR SCREEN! There is a button on most keyboard that says Prt Scr (or print screen). On my keyboard it shares a key with SysReq, but it still works.
First, close (not minimize, close) all of the windows you currently have open. Press the print screen button. If you don't know where it is, look at the picture. It should be around the area to the upper left of the keypad.