If you still want AV software you can try clamwin which is open source: https://clamwin.com/. Source: 11 months ago

If you really want to install something, try ClamAV (or ClamWin for a GUI). Source: over 1 year ago

I do. You can use ClamWin if you want an AV local to the machine. I typically keep the retro computers on their own network that can't communicate with my home one. Just use common sense. You'll probably want to try RetroZilla on 98. If you're comfortable with your 98 PC connecting to a modern machine on your network, WebOne has given me more browsing capability across any browser. Source: almost 2 years ago

Try Clamwin. But even if it works it will take ages. Source: over 2 years ago

If you really need another antivirus alternative for whatever reason the only recommendation is ClamWin which is based on ClamAV which is basically the only open source antivirus option available, but it don't real-time scanner.ClamWin which is based on ClamAV which is basically the only open source antivirus option available, but it don't have real-time scanner so you need to scan the files manually. Source: almost 3 years ago

Everything you are talking about already exists and has for years. If you do want to stress yourself out, go check out things like https://darktrace.com/ or you read up on what DARPA has in terms of AI and software that can defend & patch itself against attacks and write its own exploits, https://arstechnica.com/information-technology/2016/08/the-world-series-of-hacking-without-humans/. They brought them to DEFCON... Source: about 1 year ago