Ever downloaded something from the web and the next thing that happens, you notice something goes wrong with the computer? When something like this happens, there is a very big chance that the system has been infiltrated by a virus, spyware or adware. Everyone surely knows how dangerous viruses can be. It can shutdown the entire computer that will cost the individual a lot of money just to have it repaired. But what about spyware and adware? How dangerous are these?