All this odd behaviour began to stack, and it wasn't long before my faithful old machine started to chug. All along I suspected a virus, but I hadn't downloaded anything particularly suspicious, and repeated Defender scans came back negative. Eventually, I decided it was time to reach out for a second opinion, and with a gulp I deactivated the Windows program and installed Bitdefender's free version, more for a proof of concept than anything else. The first scan revealed my fears had come true: