Microsoft Security Essentials : http://windows.microsoft.com/en-US/windows/products/security-essentials
MSE and Avast free version will be great, use MSE as primary, then install Avast as secondary protection
AVG used to be the shiznit a few years ago, but they're gone all goony lately typically MSE alone should suffice, but if you often have 'malfunctions', getting a secondary protection isn't so bad, again I recommend Avast because when you install, it lets you install as 'secondary protection' so the two does not conflict
Great Article on running multiple antivirus softwares. http://lifehacker.com/5898756/why-you-shoulder-consider-using-more-than-one-antivirus-app MSE and Malware Bytes for me.
AVG, MSE or Avast, it really doesn't matter which one you get. Choose one and you're set. I use Avast and like it a lot. Free Virus Scanner Comparisons.
I've ran MSE ever since it came out and have had no viruses, then again, I'm barely on my windows side and am always using os x
Get the pro version of malware bytes for like 20 bucks i believe. It does automatic updates and block constant threats. I mean you could settle for free but you have to be sure your virus protection is up to date.
You can make a scheduled task yourself to update Malwarebytes. Takes a bit of work, but not terribly hard to do.
AVG is terrible now, I'd stay away. MSE and Malwarebytes is probably the best free combination 0 Not much of a discussion.