You unplug the ethernet cable. Grab a USB drive. Back up only your irreplaceable photos and documents—nothing else. Then you wipe the drive clean and reinstall Windows from scratch.

Your friend sighs. “Yeah. That’s probably it.”

That’s when you notice your browser acting strange. You search “how to remove persistent malware,” and the page loads twice—first a blank white screen, then the results. Your cursor moves on its own for half a second before you jerk the mouse.

The antivirus cleans them. Reboot. Another pop-up.

You run a full scan. It finds seven more threats hiding in your registry, your startup folder, your scheduled tasks. They’ve been living there for days, phoning home to a server in a country you can’t pronounce, slowly turning your machine into a zombie for someone else’s botnet.

At first, you ignored it. Just a false positive, you thought. But yesterday, the pop-up appeared while your computer was idle. You weren’t even downloading anything. That’s when the itch started—the quiet, sinking suspicion that something is wrong.