Windows now includes its own antivirus software, Windows Defender (as of Windows 8). Previous versions of Windows Defender only provided security scans for spyware, adware, and some ad-based rootkits.

At the time, Microsoft feared both regulators, and pushback from the antivirus industry. Hence, Windows Vista and Windows 7 lacked comprehensive antivirus and antimalware security. Apple routinely, however, took advantage of this and took advertising shots at Microsoft for shipping an insecure product. Ultimately, Microsoft relented and ported their server-side antivirus technology to consumers, in the form of Microsoft Security Essentials (MSE). In Windows 8, Microsoft merged MSE and Defender into Windows Defender.

On Windows RT, Windows Defender is the only antivirus product allowed – Microsoft has banned all other antivirus apps, as part of its lovely (sarcasm) Walled Garden. Since there’s no ActiveX on Windows RT, a antivirus maker can’t even offer the old classic Internet Explorer virus scans of the early-to-mid 2000s.

But, today Windows 8 is on the uptick. And, while Windows Defender is free, it is viewed by most as not the best antivirus on the block. Still, the economy is still terrible for most consumers, and Defender will have to do.

Enter the world of free antivirus scanners, which can serve as a backup/augmentation to Windows Defender. One of the main guns in this business, is Kaspersky. They actually offer three different, free tools for virus scanning and removal.

If you’re confused as to which one you should use, you’re not alone. In fact, for most, you should use more than one. Here’s a primer on what they do:

Kaspersky Security Scan (KSS) – This tool is akin to the web virus scans of old. It’s a Windows app that scans for both security risks and malware, and delivers a report as to what is putting your computer at risk. It does not remove or address any security risk. Virus definitions are downloaded after installing the small tool, and automatically updated from the cloud.

Kaspersky Virus Removal Tool (KVRT) – This is a free virus removal tool. It includes in its download a full virus definition profile, for offline use out-of-the-box. It also will update the virus definitions from the cloud with manual update controls. It does not scan for security exploits other than malware, such as needed Windows Updates or attack-prone older versions of key apps.

Kaspersky Antivirus Rescue Disc (KAV) – This is a boot disc (ISO image) for x86 and x64 Windows PCs. It will run from a CD-R or from a USB flash drive, when properly formatted.

So, which to use? Most should run Kapserky Security Scan, and park a copy of Kaspersky Virus Removal Tool on a flash drive. You should also burn a CD or flash drive with Kaspersky Antivirus Rescue as an emergency tool. Here’s the logic.

Obviously, Windows Defender is the primary antivirus tool. But, it’s not perfect. So, run weekly scans with KSS. If you get a virus, you’re going to need to run Kaspersky Antivirus Rescue to remove it (assuming Windows Defender fails you). And, if you do get a virus, it may not be removable while Windows is running, which is where Kaspersky Antivirus Rescue comes in, removing the virus while Windows is offline.

Is it elegant? Not really. You’re talking about having to schedule/remember to run KSS once a week, and then have multiple tools at hand for what happens if you do get hit. Windows Defender does offer good protection if you aren’t a major target (downloading torrents, attracting multi-national governmental spying, or anything similar). And, if you have more than three Windows installs, managing antivirus subscriptions, deals, and mail-in rebates becomes a hassle on its own.

So, now you know what to do, and decide if it makes sense to buy antivirus, or go the free route with Kaspersky’s free tools.