Computer viruses come in many forms and similar to the viruses that affect human beings, they can affect your computer in different ways. A computer virus can delete files, steal data such as your passwords or credit card information, or damage other devices on your network. There are several types of computer viruses, each triggered by different actions and all affecting various parts of your machine. A Boot Sector Virus is difficult to remove and almost always requires a full system reformat. A boot sector virus is often spread through removable media, such as floppy disks or USB drives or even in email attachments. One of the most common and well-known virus types are Trojan Horses often sent to your computer by a program hidden inside of it. Overwrite Viruses can take over a file and infect it with information or even delete it. A Browser Hijacker virus takes over parts of the Internet browser being used and can redirect it to specific sites.