Nowadays, trojan and worm virus is an headache of every computer users that it seems uncontrollable even your anti-virus software is always updated. It seem so helpless specially for ordinary user of computer. The use of USB drives or what they call thumb drive is one of the major spreader of these virus in addition to Internet connection. But are you aware that the spread of this called bugs or virus can be prevented even you anti-virus is not so powerful? Here is how: