Poor you! What kind of protection do you have?
I use Avast and Malwarebytes and Web of Trust. So far, no viruses and yes, there are people who use my computer to look up *bleep* and download junk when my back is turned (lol ok that's me as well). But luckily, nothing for months, and the last one was pretty easy to get rid of.
Those are also the three things I put on my siblings computers, when they asked for help setting up their computers. Other than my brother complaining that he has to click twice (yes, I want to see this site) to get to his *bleep*, nothing. And I just checked his computer for him last week and he's had the thing nearly a year (I know because he never ran Malwarebytes lol Outdated by 340+ days *sigh* why do I bother? Still, found nothing so all good). He doesn't download though and only plays on it occasionally (it's a laptop and he doesn't actually have internet access at his house), so dunno how much he really uses it.
Everyone's different in their internet habits and they may not work for every situation (especially if you already have a virus program, as more than one tends to get tangled in each other).
But I think they're pretty good for just about everyone, in general, since, as another example, I had an ex-roommate that crashed computers before, but with his new laptop I set up for him (as far as I'm aware) it is still working for him. He's awful about *bleep* and downloading viruses that mean you have to wipe the entire hard drive and fresh install things.
Anyways, it's always good to keep on top of these things! Can never be too careful, right?
So I think I'll go run Malwarebytes right now!