The most useful thing in this computer world is World Wide Web, at the same time it is more dangerous to our computer too. We need to be more careful while connecting our computer with world local net called Internet. There are many sites waiting to inject virus and worm in to our computer. If it enters our system then it is difficult to delete or heal. Some steps must be taken before we connect to the Internet. First and most thing is we should install Anti-virus in our hard disc as it prevents entering of virus in our system. we need to update frequently. Please keep fire wall in on position always. Scan your system frequently as it helps to delete unwanted files in our systems and improves operating speed. Be cautious while downloading from Internet. When ever you download something from Internet please check whether it is virus free file or not. while run any installation file keep your anti-virus application in scanning mode. If you download and install any application from net, it may have some file so that end user can view and access your system. It is most dangerous thing in Internet. So take extra care while using Internet. Better avoid any personal file in the system which is going to be connected with Internet. "Prevention is better than cure"