I have never had malware infections on my PCs from W.XP onwards.
Today I can understand if a PC has something that does not go only with its use.
I don't think you care about my opinion when I was young and inexperienced because I should talk to you about prehistoric OSs.
However, I relied on excellent anti-malware products and removed the remnants of malware manually.
This is still possible today for example with Hitman Pro.
In my pc with XP I can still use HijackThis Portable.
But it's like knowing how to use an old manual slide rule.
You know the one used also in the movie "Apollo 13":
en.wikipedia.org
Also the use of Adwcleaner I remember that was very useful to me.
With Linux I remember that I used a lot of tools to check for rootkits.
P.S.
I remembered that I still have a slide rule in my desk drawer.
I went to check it out.
Who knows maybe it will come in handy in case of:
en.wikipedia.org