Steps To make your own Antivirus.

Open your Notepad and paste this given code 

@echo off
title Antivirus
echo Antivirus
echo created by your name
:start
IF EXIST virus.bat goto infected
IF NOT EXIST virus.bat goto clean
cd C:\Windows\system32
:infected
echo WARNING VIRUS DETECTED!
del virus.bat
pause
goto start
:clean
echo System secure!
pause
exit


Now save your file with Computerfreaks.bat and select "All files" 

now run your saved files automatically scan starts