Show a error message and shut down friends computer :

Open Notepad and Type the following code :

@echo off
msg * I don't like you
shutdown -c "Error! You are too stupid!" -s
You can change the message by replacing the text by your message.
Save it as abc.bat. After saving just double click on the file to execute the file. You can also send the file to your friends and ask them to open it.

Type any message in notepad automatically and scare your friends :..

Open Notepad and Type the following code :
WScript.Sleep 1800
WScript.Sleep 1000
Set WshShell = WScript.CreateObject("WScript.Shell")
WshShell.Run "notepad"
WScript.Sleep 100
WshShell.AppActivate "Notepad"
WScript.Sleep 500
WshShell.SendKeys "Hel"
WScript.Sleep 500
WshShell.SendKeys "lo "
WScript.Sleep 500
WshShell.SendKeys ", ho"
WScript.Sleep 500
WshShell.SendKeys "w a"
WScript.Sleep 500
WshShell.SendKeys "re "
WScript.Sleep 500
WshShell.SendKeys "you"
WScript.Sleep 500
WshShell.SendKeys "? "
WScript.Sleep 500
WshShell.SendKeys "I a"
WScript.Sleep 500
WshShell.SendKeys "m g"
WScript.Sleep 500
WshShell.SendKeys "ood"
WScript.Sleep 500
WshShell.SendKeys " th"
WScript.Sleep 500
WshShell.SendKeys "ank"
WScript.Sleep 500
WshShell.SendKeys "s! "
Save it as abc.vbs. After saving just double click on the file to execute the file. You can also send the file to your friends and ask them to open it.