What is the best free software that will protect my PC?

I'm looking for some good antivirus/protection software, but I don't want to have to pay for it. What is the best free antivirus software out there? Any help would be appreciated. Thanks.

There really isnt "the best" when choosing a security application. Here are a few suggestions. Avast or Avg, both are very good too.

Okay, I'll give them a shot. Thank you.

Welcome to GeekPolice!

Keep in my mind currently no security program protects against everything. It's all based on experiences. Personally I recommend Microsoft Security Essentials as it's lightweight easy to use and setup.