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What's the deal with your nickname? How did you get it? If your nickname is self-explanatory, then tell everyone when you first started using the internet, and what was the first thing that made you say "wow, this isn't just a place for freaks after all?" Was it a website? Was it an email from a long-lost friend? Go on, spill it.

The easy argument on Microsoft Windows is that you can use their virus scanner, which is unique in the lack of nagging or scaremongering.

https://en.wikipedia.org/wiki/Microsoft_Security_Essentials
https://en.wikipedia.org/wiki/Windows_Defender

You need more than MSE or Defender to provide security assurance. It's a baseline, particularly because they share their virus signature database with other companies for free, and virus scanning is all it does. But similar things can be said of all the virus scanners.

It's infuriating how little help anti-virus sellers provide in making sure your software is up to date with security fixes, which should be #1 on your checklist.

#2 on the checklist is your browser. (Chrome, Edge, or Firefox in that order; that applies to all OS's. I'd be superstitious about allowing Flash in Firefox, even on Windows where it's a bit better. Set Flash as click-to-play in your non-Firefox browser which you use for Flash content)

Make sure not to disable Safe Browsing (Microsoft: Smartscreen Filter). If you have privacy concerns about this, use Google Chrome, because the code used is documented, open-sourced, and does not transmit your browsing history. (Other Chrome features might, but you can turn them off safely and without too much effort).

There's a half-finished site by a security professional, which points out that the default install of Chrome is not ideal. The system install, with 64-bits, is what Chrome engineers actually recommend:

http://decentsecurity.com/securing-your-computer/

My main complaint about that site is that it hasn't mentioned ransomeware. Where the fallback you want to have is a comprehensive backup. Note that user-writable storage (e.g. USB or Dropbox) is equally vulnerable to ransomeware. "Cloud" backup comes with a monthly cost. Crashplan comes highly recommended and supports peer-to-peer backup at no cost... and I should really try my own advice here because my backup is too much of a system-specific hack.

People who understand that and more, who actively maintain their knowledge and their systems, can pretty much guarantee to be happier without a third-party virus scanner. And there are valid reasons to give up on even with the first-party one; for example leaving real-time scanning enabled will often slow you down if you're using the computer to develop your own software.