A virus is a program created by some one who likes to hack into peoples computers.A virus attacks your whole computer by crashing it,deleted and sending files through the internet without permission,watching what you type in,finding out credit card numbers.Any infomation on your pc is open to a virus unless you have whats called a firewall,or an antivirus program like Mcfee©.There is another type of virus and thats called spyware.But this one basically is an advertisement program and can work in some ways as a virus.Hope this helps.
jonny, June 2006