>>i want to create a anti virus using batch file..
Oh, Great, I hope you succeed in your attempt but one question...
" How Is This Related to C++ ?"
Batch Files can be created with the help of a normal text editor itself. Even If you want to use C++ to create a batch-file I dont think that anyone can comprehend the way viruses work with ease.
>>our school got a lot of virus that ruin my usb.. please help me..
Well, If your School Computers are filled with viruses why dont you ask your schools System Administrator to Install a Good Antivirus software. There are many of them which are available for "FREE".
Anyways, THUG LINE, The only Advice I can give to you is that It is essential for you to read this!!