How to clean viruses off your computer for free

Last Updated on March 13, 2021 by Dave Farquhar

Whether you’ve gotten a tech support scam phone call or not, it can be helpful to know how to clean viruses off your computer for free. And yes, I do mean free.

A lot of people get ripped off due to virus scares and it makes me mad. I’m a computer security professional. I advise large companies on computer security for a living. Today I’ll take a few minutes to advise you.

First things first. It would be malpractice if I didn’t mention that the only way to be completely certain your computer is virus-free is to reformat the drive and reload from your manufacturer’s rescue DVD, or a legitimate copy of Windows that came from Microsoft. Then reload your software and restore your data from backup. That’s the safest thing to do.

But I’m a realist. Most people aren’t going to do that.

Still with me? Use a clean computer to download the Bitdefender rescue CD and burn it to a CD or a USB thumb drive. Then boot your system off the drive. Here’s some help getting an HP or Compaq or a Toshiba computer to boot off USB if you need it. Connect your computer to the Internet after it boots. A wired connection will be easier, since the Bitdefender rescue CD or USB runs off an operating system called Linux and may or may not find your wireless adapter. Bitdefender will then connect to the Internet, pull down virus definitions, and clean up your computer. Since it contains its own operating system, it can dig deeper into what’s on your drive and find things that can hide from your live system.

After Bitdefender finishes, you can restart, remove the CD or USB stick, and let Windows load. At that point I recommend you download and install Malwarebytes.  The free edition is fine for home use, especially these purposes. Malwarebytes is a bit more aggressive than other antivirus software. So don’t it may find things Bitdefender left alone. If this isn’t something you do every day, let Bitdefender delete or quarantine anything it finds suspicious.

At this point I would recommend reinstalling whatever antivirus software you normally use. It may have become damaged in the process of your computer getting infected or reviving it. If you normally use a free antivirus program, just uninstall the old copy, download a new one, and reinstall it. Sometimes your antivirus software will refuse to uninstall. If your virus damaged your old antivirus software to the point where it won’t uninstall, try Appremover.

If you use a paid one and you don’t have a copy on DVD, contact the vendor to find out where to get a clean, up-to-date copy. Get a clean, up to date copy before you uninstall the old one.

As far as which product I recommend, for home use I generally recommend Microsoft’s Windows Defender (for Windows 10) or Security Essentials (for Windows 7). The most promising antivirus technology out there right now comes from a company named Cylance, but they don’t have a consumer product and I don’t know if they plan to make one. For now they are happy selling antivirus to businesses.

But that’s more than what you came for. What you really came for was advice on how to clean viruses off your computer for free. I hope you found this helpful.

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