A boot sector virus is a virus that places its own codes and commands into a computer's DOS boot sector or Master Boot Record (MBR). When a boot sector virus has infected a system, the MBR is usually corrupted and a computer's boot sequence is changed. Since the MBR is located on the first sector of a computer's hard disk, the virus is called a boot sector virus.

Boot sector viruses can be dangerous and prolific because they are loaded onto a computer every time one starts up. In time, they can spread to other readable disks. Booting problems and start up problems, problems with retrieving data, computer performance instability and the inability to locate hard drives are all issues that may arise due to a boot sector virus infection.

One of the main ways a boot sector virus infects computers is through floppy disks. Due to technological advancements, these disks do not have to be the old-fashioned bootable disks to do damage to a system- they can be average disks that have been left in drives when computers start up. The virus can also thrive in shared networks where files are exchanged and email attachments are distributed.

Fortunately, boot sector virus removal is easy. Using common antivirus software can remove the virus quickly and efficiently. However, it is important to find an antivirus software that is capable of removing the virus completely. Failing to do so can result in a partial removal, which can then lead to a different part of a hard drive being effected. Investing in an antivirus software can also help protect data and files during the removal process.

Prevention of infection is also simple. Users should avoid sharing diskettes and illegally downloading software since the virus can be transmitted both these ways. Removing disks from drives before starting up a computer can also spare a user from infection since the virus can reside in a floppy disk. Installing a live antivirus software that actively assesses threats to a machine may also help in deterring attacks.

All users should be prepared for a virus attack any kind. Generally, it's a good idea to regularly back up files. Keeping system disks locked so that viruses are not able to write them can protect disks from unwanted intrusion. Checking all downloaded applications for viruses before installation and locking floppy disks before using them in a third-party computer can also keep a user's personal computer virus-free.