Computer viruses come from troublesome computer programmers who range from annoying jesters to greedy criminals. A computer virus is a program that hides within another program. When you run (execute) the containing program, you also run its virus, which causes your computer to act strangely. The extent to which a virus disrupts your computer varies according its strength. A weak virus might only display a message or play a sound. In contrast, a strong virus might destroy data or uninstall software.
Computer viruses are only one type of malware (malicious software). The other two major types are worms and Trojan horses. For more information, see What are Viruses, Worms, and Trojan Horses?
Computer Virus Infections
Viruses can infect your computer through downloads, email, or portable media.
Infections Through Downloads – You can infect your computer if you download any program that contains a virus. Try to download files only from reputable websites. If you visit a rogue (dangerous or deceptive) website, you can inadvertently download a virus-infected program. For example, you might accidently click on a brief pop-up ad, or leave a box checked at the bottom of a seemingly-innocent page. Also, many rogue sites promise to protect you (through downloads of course) against viruses and other malware, but actually deliver them.
Infections Through Email – You can infect your computer with a virus if you open an email attachment from an unknown source. Even if you know the sender, do not open an email attachment if it seems at all suspicious; for example, if neither the email title nor the attachment file name make sense.
Infections Through Portable Media – You can infect your computer by loading a program through a CD, DVD, memory stick, or other portable storage media. For example, be suspicious if a ‘friend’ gives you a CD while saying it contains a useful program.
Guarding Your Computer Against Viruses
To guard your computer against viruses, you can:
- Surf the internet carefully.
- Scan for viruses.
- Backup your data.
- Backup your computer.
Surfing the Internet Carefully – Avoid rogue websites because they can infect your computer with viruses and other malware. If possible, use browser and/or security-suite tools to validate a website’s link before you click on it. For example, the Computer Associates Security Suite displays tooltips that validate honest websites and identify rogue websites. To compare various security suites, see: PC Magazine Windows Security Suites.
Note: Whichever security suite you choose, make sure to set it up to receive automatic updates. An out-of-date security suite is useless.
Scanning for Viruses – You can use free antivirus software, such as AVG Free to scan for viruses. Alternatively, for protection against all malware, you can either use the security suite provided by your internet provider, or purchase a separate security suite. You can setup or schedule virus scans that:
- Automatically scan the files and programs you use while working on your computer. This is called real-time protection.
- Scan one or all hard drives.
- Scan one or more folders.
- Scan one or more files. For example, if you are suspicious of a download, you can download that file to a ‘test’ folder, and then scan it before you open it.
Note: Max and Linux computers are currently less vulnerable to viruses than are PCs. However, you can obtain antivirus software for your Mac or Linux computer. Two examples:
- iAntiVirus – Free AntiVirus for Mac
- Avast Linux Home Edition
Backing Up Your Data – You should frequently back up your data, preferably daily. Copy your personal data files to either a separate hard drive or to removable media. If a virus gets past your antivirus software and erases some data files, you can restore them if you have made a data backup.
Backing Up Your Computer – You should regularly make a full-system backup (back up your entire computer), preferably weekly. You can use Acronis True Image Home to create an image of your hard drive and store it on an external hard drive. If a virus gets past your antivirus software and corrupts so many data and program files that you need to reload your operating system, you can restore all your installed software and settings if you have made a full-system backup.