Unless you’ve been living under a rock for a few years, you’ve probably heard the term "computer virus." A virus is a malicious program that can damage data by corrupting programs, deleting files, or reformatting your hard disk. However, computer viruses are not necessarily damaging. Some just reproduce themselves or display obnoxious messages. You can get a virus and never lose any data.
Note that a virus can only damage software. For example, even though a virus can cause your screen to look weird, the monitor itself isn’t damaged. The virus is affecting the software that controls the display. Although e-mail attachments can include viruses, viruses can’t do anything to a text-based e-mail message itself. An HTML e-mail message can include virus code that runs automatically, whereas a text based e-mail can’t do anything on its own.
When you run anti-virus software like Norton AntiVirus (NAV), you run into a number of terms that can be confusing if you don’t really know what the software is up to. For example, NAV has a feature called Auto-Protect, which scans your files every time they are used. It checks files against a list of virus definition files. Virus definitions contain the information that NAV uses to detect viruses, which is why it is important to keep your definitions updated. NAV includes a feature called Live Update that you can use to download updates automatically, so you don’t forget about it.
Inoculation is another term you see in conjunction with viruses. After NAV scans your disk, it "inoculates" the boot records your system uses when it "boots up" to make sure they stay free of viruses. Inoculation records information about the file, so if a virus attacks it later, NAV can detect any changes during later scans and fix the file.
If NAV detects a virus and can’t repair the affected file using its current set of virus definitions, it "quarantines" the file. Files that have been quarantined can’t interact with the rest of the system, so the virus can’t spread. NAV stores backups of any files it changes during a repair in the quarantine area as well. After you have determined that the fix was successful, you can delete these back up files.