Once you get a virus on your system it really opens the door for other viruses and malware it can even effect other computers on the same network. People who do have a virus on their computer usually have more than one. Viruses can get so deep by attaching themselves to system files it sometimes breaks the system if you remove it, certain things may not work anymore.
Even by running the latest anti-virus program you cannot be 100 percent sure it removed everything, some of the best anti virus programs have about 98 to 99 percent success rate, so what about that other 1 to 2 percent? Check out the result of anti virus testing done by AV-Test.org.
Back in the day viruses were about vandalism doing stuff like formating your drive or opening and closing the CD tray, nowadays it’s all about sneaking into your system without your knowledge because thats how they make money by selling your computer resources to spammers or hackers.
So the best thing you can do to remove a virus is starting over by formating the hard drive and installing a fresh copy of Windows. Make sure you have all the disks that came with the computer, they usually they come with System Recovery disks. Back up all your data because you will lose everything, this will erase the hard drive and will take your computer back to the very first day that you got it.
The best way to get rid of a virus is by not getting it in the first place, anti virus programs are good but they are your second line of defense your first line of defense is you. By changing your online behavior and knowing what not to do or “safe computing” as some people would call it. Avoid things like opening email attachments, clicking on links in emails, avoid downloading pirated software, pirated music and movies, and especially avoid going to porn sites no matter how tempting it may be.