How Antivirus Programs Work - dummies

By Dan Gookin

To properly fight viruses, you should get an antivirus program. That’s because Windows itself doesn’t come with antivirus software. If your PC came supplied with antivirus software, it was most likely a trial version. The antivirus program you choose should have two modes of operation:

Interactive: In this mode, the program lurks in the background and monitors the computer’s activity. Specifically, the interactive mode looks for a virus coming in from the Internet (a download or an email attachment) or delivered on removable media.

Scan: In this mode, the antivirus program probes all parts of the computer’s memory and storage system, looking for signs of infection. You can direct the program to scan your PC at any time, though traditionally an antivirus program scans the computer when it first starts.

When a virus or sign of infection is found, the antivirus software alerts you to its presence. The virus may be destroyed or the file quarantined for later examination. Either way, whatever operation the virus was set out to perform is thwarted.

  • It’s possible to be vigilant and avoid using antivirus software. But that big, looming monster called Doubt plays a role in how you use your computer. Nasty software exists. Even if you don’t run an interactive antivirus program, you should use antivirus software to scan your computer routinely for signs of infection.

  • Antivirus software requires frequent updating. Normally, you subscribe to the antivirus developer’s website, allowing downloads of new virus definitions and protection information. Only by keeping your antivirus software up-to-date do you ensure that your computer can battle new and malevolent threats.

  • Yes, those subscriptions cost money. But consider that the cost is far less than the cost of taking your computer into the shop to have a professional rid your system of infection and restore your data.

  • You can run more than one antivirus program at a time. In fact, having two antivirus programs is a great way to boost your PC’s security. For example, you can run either Norton or McAfee antivirus software as your primary protection. Then, every so often, run a secondary program to perform a scan-only; the secondary program may find things that the first program misses.

  • If you choose to run two antivirus programs at one time, place only one into Interactive mode. Running two antivirus programs in Interactive mode doesn’t help fight viruses and instead merely slows down your computer.

  • Avoid using web-based antivirus scans, because most of them are malware — either spyware or Trojan horses. It’s okay to download an antivirus program from a legitimate developer on the web, but don’t use any antivirus software that runs from a web page.