Well, that explains it. Good thing it wasn't a virus but running those two antivirus and antimalware software's, you'll never have to worry. I'm running those two and I haven't had any problems with viruses.
I always say Google comes in handy. You were able to show patience and read about it for that long, that's good. If it was me, I'll be too busy being pissed off and not focusing on any solutions. Patience is not one of my strong virtues.
I'm glad you were able to fix it. I had the blue screen of death on my first newly bought computer. Seriously, I just bought it and after a few days, blue screen of death. I didn't do anything to it. I was angry but I took it back and they gave me another one.