Canadian Politics Today

I checked the online reviews and their reviews of Windows Defender were not kind. It's possible your malware detector doesn't pick anything up because it's not very good, you know.

People trash Windows Defender but a little perspective is worthwhile:
http://www.howtogeek.com/225385/what%E2%80%99s-the-best-antivirus-for-windows-10-is-windows-defender-good-enough/

Overall, Windows Defender doesn’t provide bad protection, assuming you keep Windows up-to-date, use an up-to-date browser, and avoid potentially dangerous plug-ins like Java. In short: the standard computer security practices you should be following go a long way, and Windows Defender combines that with a baseline of protection.
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 However, when it comes to actual statistics, AV-TEST found that it still caught 99 percent of the “widespread and prevalent malware” in October 2015, along with 95 percent of the zero-day attacks. AV-Comparatives real-world protection tests found that it caught 94.5% of threats.
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In short: Windows Defender isn’t bad, per se, it just isn’t as good as your other options. However, it’s by far the least intrusive, considering most other antivirus programs come bundled with crapware, install problematic browser extensions, and contain occasional popup ads.

I personally use Windows Defender and use a VM if I need to access dodgy sites. Virus programs are simply too intrusive for my taste.