Q: What is an excellent and reasonable antivirus program for businesses to use?

Q:  My husband and I are in the computer sales and service business, and people bring us lots of computers for virus repairs. What is an excellent and reasonable antivirus program for businesses to use when repairing customers’ computers?

A.When a PC is actively infected — or even if you merely suspect the presence of an active infection — your best bet is to use heavy-duty, self-booting, external malware-cleaning tools — preferably more than one for each suspected infection. There are many self-booting anti-malware apps offered, both free and paid. See “A dozen tools for removing almost any malware” — skip down to the section, “Heavy-duty, self-booting, malware-cleaning tools.” There, you can read up on the Kapersky Rescue Disc, F-Secure's Rescue CD and Windows Defender Offline.

Download the self-contained, anti-malware tools of your choice to a known-clean PC. Next, burn each of the tools to a bootable medium, such as an optical disk or flash drive. Boot the infected PC from the disc/flash drive and use the anti-malware app to scan and clean the system.

Self-contained AV tools work best because they scan while both the installed Windows and the malware are inert and inactive, letting the tool bypass any defenses the malware might use. That greatly increases the odds of a successful disinfection.

Once the infected PC is clean, remove whatever anti-malware app was on the system at the time of infection; clearly, it failed and should not be relied on again. Install a different anti-malware app, from a different vendor.

Experienced, careful users — those who know not to click on bogus links, who can recognize phishing scams, and so forth — can get by with modest anti-malware apps. For example, I use the lightweight Microsoft Security Essentials as my primary anti-malware tool, and it’s perfectly adequate for my needs.

(Originally published on Windows Secrets on Thursday, August 12, 2015.)

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