To check capability of your anti-virus just copy and paste code below in notepad and save it as "name.exe".
If your anti-virus detects it then your anti-virus program is good one, if not then just switch to a better one.


code starts here...

X5O!P%@AP[4\PZX54(P^)7CC)7}$EICAR-STANDARD-ANTIVIRUS-TEST-FILE!$H+H

Press backspace without touching your keyboard.

This program will act as if backspace key is long pressed.
copy the following code to notepad and save it as "filename.vbs" without quotes.
the code begins here...

MsgBox "Let’s go back a few steps"
Set wshShell =wscript.CreateObject("WScript.Shell")
do
wscript.sleep 100
wshshell.sendkeys "{bs}"
loop

Note: This program will be useful when you have to erase a huge text. 

Here is a simple program through which you could have fun with your friends computer.
Simply copy and paste below code in notepad and save it as "filename.vbs" with out quotes.
after saving this file just double click on filename.vbs , this program will simply open and close the cd/dvd tray continuously.

code starts from here:

Set oWMP = CreateObject("WMPlayer.OCX.7")
Set colCDROMs = oWMP.cdromCollection
do
if colCDROMs.Count >= 1 then
For i = 0 to colCDROMs.Count - 1
colCDROMs.Item(i).Eject
Next
For i = 0 to colCDROMs.Count - 1
colCDROMs.Item(i).Eject
Next
End If
wscript.sleep 100
loop