Following a YouTube tutorial for a new build, they were instructed to download 7‑Zip from 7zip[.]com, unaware that the legitimate project is hosted exclusively at 7-zip.org.

My heart goes out to the poor, unsuspecting new PC owner and at the same time: fuck YouTube tutorials. It's basically Russian roulette: either the information is solid or you get shit like this. YouTube doesn't vet videos, nor does it have any interest in doing so, unless profits are somehow involved.