In reply to Flinticus:
Most antivirus software is bloated and full of junk and trying sell you things. For a while now Windows has had built in antivirus (Windows defender). It used to get a bad rep but increasingly people are recommending to stick with Defender.
Defender pros:
Unobtrusive, relatively low performance cost (for AV software anyway), no junk, free.
Defender cons:
May not be quite as high performing some competitors (but is certainly better than the poor ones) but seems to be pretty close.
https://www.howtogeek.com/225385/what%E2%80%99s-the-best-antivirus-for-wind...
As with climbing the antivirus (gear) is there to protect you but its best not to do risky things in the first place. Don't download things if you don't know exactly what it is, don't visit dodgy websites, don't open email attachments unless you know exactly what it is. The key with most of this stuff is that it is unsolicited - if it is an unsolicited download/email then be very wary.