I was watching The Screen Savers on TechTV the other day and this guy called and said that he had something on his computer trying to do a DOS(Denial Of Service) Attack on a Korean(I think) server. he said he had ran anti-virus and stuff. They told him that they could especially if you said to download it from anti-virus and that it is going to be very hard to erase. They told him to run some more stuff and if that didn't help that they would say to re-install windows. IS this all true is it possible for it to hide from anti-viruses? Also would it be possible for a trojan on your computer and even threw scanning your computer with spyware removal tools and Anti-virus for it to still be there? I'm a newbie when it comes to viruses and stuff so if anyone could help please help me.