On several occasions recently, I came back to my computer to find it running programs I knew I hadn't left open. I asked my girlfriend if she had been using my computer and she said no. I wondered what was going on, and I suspected a virus or other malware. I ran various antispyware and anivirus programs, but found nothing. The other day I came into my room and found that the computer was turned off, even though I knew I left it on. What kind of virus turns the system off? What kind of virus only strikes when I leave the door to my room open?
Then I finally put together all the clues. I don't have a virus. I have a cat who likes to walk on the keyboard when I'm not in the room.