Viruses are more sophisticated since they started gaining wide notoriety in the 1980s. When Norton AntiVirus and other tools were successful at detecting and removing viruses from computers, the struggle was on: The people who wrote viruses knew they had to stay one step ahead; they developed ways to make their viruses more difficult to detect.
No need to go into niggling detail about the various types of viruses here (unless you want to start a second career writing some of your own — in which case, too bad). But the next article profile some general ways the little monsters work — in case you want to decide for yourself whether antivirus tools are really worth the money.
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