A computer virus, is a malicious software that can do harm or damage your computer. They can be accessed by downloading or entering certain sites. They are a form of command prompts that tell the computer what to do, in a bad way. Virus protection and Firewall were created to block these so called "viruses". They originate from hacker or other things. Just like a human virus, it can be transfered from "touch" or using a data storage tool and putting that same tool in another computer.Some malware is programmed to damage the computer by damaging programs, deleting files, or reformatting the hard disk. Other malware programs are not designed to do any damage, but simply replicate themselves and perhaps make their presence known by presenting text, video, or audio messages. Bug-ridden malware can crash your computer or format the hard drive. It is difficult to stop problems caused by viruses when they have begun.