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A computer virus is a program designed to spread itself by first infecting executable files or the system areas of hard and floppy disks on your PC and then making copies of itself. According to antivirus firm Sophos, the number of known viruses is approaching 80,000, and will keep on growing as more are created.
There are many different types of computer viruses or similar programs, including:
- Boot sector viruses, which replace the boot sector program with their own infected version when you start your computer using an infected floppy disk or bootable CD
- Macro viruses, which 'infect' a Microsoft Office or similar application and cause their payloads to be triggered when the application is started
- Worms, which can infect your PC if you double-click on an infected email attachment and can resend themselves to all the entries in your email program's address book
- Trojan Horses, which are programs that pretend to do one thing but do another - for example deleting files from your hard drive rather than starting up a new game
Viruses can get into your computer when you receive an email with an attachment, download something from the Internet, open files on a floppy disc or even view a web page. Virus code must be executed to have any effect, so virus code has to be in a form, such as an .exe program file or a Word .doc file, that the computer will actually try to execute.
Viruses usually operate without the knowledge of the computer user, so once you are infected the virus can deliver its payload and spread itself to other machines before you even know it's there.
Antivirus software is essential. This is software that scans emails and files to detect any suspected viruses - either only on request or whenever you access, use or create a file or directory, depending on which type you choose. The software will then flag up a warning and disable the virus. Your PC should have come with pre-loaded software, but you can also search for antivirus software suppliers on the web and download a virus scanner, normally for free.
Just installing antivirus software doesn't solve the problem automatically, though. You have to keep the virus definition files up to date, because new viruses are discovered every day. To update your antivirus software, go to the home page of your software supplier and download the latest update. This should take only a few minutes and will ensure that your software can recognize all the new entries to the virus charts. Failure to do so may make the software next to useless as new viruses will be able to get through your defenses unrecognized.
More tips for staying virus-free
- Always think before you open email attachments. Never open files attached to emails from strangers - delete them immediately
- Be cautious with emails from friends, family or colleagues - viruses can automatically spread themselves without the computer owner's knowledge. If you receive an attachment that you are not expecting, save it to disk, use your virus scanner to check it, and don't be afraid to call up the sender to ask them what it is
- Be careful if you use someone else's floppy disk because it might contain a virus. Always let an antivirus program check the disk before using it.
- Be careful when downloading files from the Internet, and only use sites that are trustworthy
- Finally, make sure that if the worst case scenario develops and you are infected by a virus, you have backed up all your personal files and information. |
