@Scavenger@octodon.social For Win7, MS's free Good Enough package is called Microsoft Security Essentials. It's not included with Windows by default. https://support.microsoft.com/en-us/help/14210/security-essentials-download is where you can get it. I highly recommend it.
@Scavenger@octodon.social User behavior best practices is probably the best way to avoid viruses and malware; don't run weird programs, don't type your password unless you type in the website name, don't use IE, don't use Java plugin, try not to use Flash, etc.
@Scavenger@octodon.social If you can set up your Windows users so that the Administrator accounts are password protected, and you use a Standard account for day to day, that'll protect you more too. Some programs, mostly games, won't run under Standard user accounts though.
@Scavenger@octodon.social Beware of "Free!!!" stuff that takes over your computer and offers to scan email and incoming ports and all that; it's probably more protection than you need and can actually make your computer *more* vulnerable.