Microsoft Security Essentials. I just don't get it. Used it, it could scan my whole computer (full scan) in just a couple of hours - lately, even though I really don't have just a whole ton of stuff on my machine, it takes upward of six or more hours for it to completely scan. It's reminding me of my old computer when it was running on its last legs, but the main difference was my old computer was barely puttering along on only 512MB of RAM (it was from a time when 512MB of RAM was impressive), and my current computer is maxed out at 8GB of RAM ("maxed out" by 2012 standards, I hear you can get up to 16GB now) not to mention I've only used up about 1/4 of my diskspace. So I have no idea why Security Essentials is slowing down so much lately.