This is the one that ultimately would have saved me despite all of my previous foolishness. I did have very capable antivirus software installed with all of the latest definition files.

Unfortunately, I had disabled the active scanning feature to troubleshoot a suspected software conflict a few days earlier and had forgotten to turn it back on. Thus, aside from scheduled scans, I was running completely unprotected from whatever malware made it onto my system. If only I had remembered to turn the active scanning back on, my AV software would have picked up the Trojan the minute I downloaded it from the Internet. The file would have been quarantined, and I would have never been given the chance to infect myself.

Conclusion:

There is plenty more you can do to protect yourself from malware, but by taking care of these four things, you will do a great deal to minimize your exposure. However, no matter how much technology you deploy to protect yourself, always remember that it is usually the human element that is responsible for security breaches. Thus, no matter how much experience you have, remember never to let your guard down, lest you end up with a story like mine.